Size: px

Start showing from page:

Transcript

1 9 class 1. Minimum path A car traveling at a speed υ at some moment starts to move with such a constant acceleration that during the time τ the path s traveled by it turns out to be minimal. Define this path s. 2. Reflection in flight In the ballistic laboratory, during an experiment to study elastic reflection from moving obstacles u, a small ball was fired from a small υ catapult mounted on a horizontal surface. At the same time, from the point to which, according to calculations, the ball was supposed to fall, a massive vertical wall began to move towards it at a constant speed (see figure). After elastic reflection from the wall, the ball fell at some distance from the catapult. Then the experiment was repeated, changing only the wall speed. It turned out that in two experiments the impact of the ball on the wall occurred at the same height h. Determine this height if it is known that the flight time of the ball before reflection in the first case was t1 = 1 s, and in the second t2 = 2 s. To what maximum height H did the balloon rise during the entire flight? What is the initial velocity of the ball υ if the distance between the places of its fall on the horizontal surface in the first and second experiments was L = 9 m? Determine the velocities of uniform motion of the wall u1 and u2 in these experiments and the initial distance S between the wall and the catapult. Consider g = 1 m / s 2. Note. In the frame of reference associated with the wall, the moduli of the ball's velocity before and after the collision are the same, and the angle of reflection of the ball is equal to the angle of incidence. 3. Three-cylinder The body, glued from three coaxial cylinders of different cross-sections and different heights, is immersed in some liquid and the dependence of the Archimedes force F acting on the body on the depth h of its immersion is removed. It is known that the cross-sectional area of ​​the narrowest (not the fact that the lowest) cylinder is S = 1 cm 2. Plot the dependence F (h) and use it to determine the height of each of the cylinders, the cross-sectional areas of the other two cylinders and the density of the liquid. During the experiment, the axis of rotation of the cylinders remained vertical, g = 1 m / s 2.h, cm F a, H, 3.9 1.8 2.4 3.6 4.2 4.8 6, 7.2 7, 3 7.5 7.6 7.7 7.8 7.9 7.9

2 4. Two in a cube The cube is assembled from identical resistors with resistance R. Two resistors are replaced by ideal jumpers, as shown in the figure. Find the total resistance of the resulting system between pins A and B. What resistors from the rest can be removed so that this does not change the total resistance of the system? If you know that a current of I = 2 A flows through most of the resistors in the circuit, how do you calculate the current in the wire connected to node A (or B)? Calculate the current flowing through an ideal jumper AA? 5. Ice spot Determine what is the maximum mass mp of water vapor taken at a temperature of 1 C, which may be required to heat the ice in the calorimeter to the melting point (without melting). The exact mass of ice and its initial temperature are not known, but these values ​​may lie in the area highlighted on the -3 m / m diagram. Specific heat -4 of vaporization L = 2.3 MJ / kg, specific heat of melting of ice λ = 34 kJ / kg, specific heat of water c = 4 2 J / (kg C), specific heat of ice c1 = 2 1 J / (kg WITH). The mass of ice m in the diagram is given in conventional units, showing how many times the mass of ice is less than m = 1 kg. The heat capacity of the calorimeter and heat losses are neglected t, С

3 1 class 1. Power time As a result of the experiment, the dependence of the power N of a constant horizontal force on the time t of its action on a bar of mass m = 2 kg initially resting on a smooth horizontal table was obtained. Some measurements may not be very accurate. determine the power of the force at the moment of time τ = 6 s; find the value of the force F. N, W 1.4 2.8 4.5 5, 6, 1.4 14.7 16.6 18.3 t, s 1, 1.5 2, 2.5 3.2 5 , 7,2 8,4 9, 2. In the hole, Rod AB touches the ledge K of a hemispherical hole of radius R. Point A moves uniformly with a speed υ along the surface of the hole, starting from the bottom point N, to point M. Find the dependence of the modulus of velocity u of the end bar B from the angle α, which the bar makes with the horizon. The rod length AB is equal to 2R. 3. Ice water Some water and ice were mixed in the calorimeter. Their exact masses and initial temperatures are unknown, but these values ​​lie in the shaded areas highlighted in the diagram. Find the maximum amount of heat that could be transferred by water to ice if, after thermal equilibrium was established, the mass of ice did not change. Determine the possible mass of the calorimeter content in this case. Specific heat of melting of ice λ = 34 kJ / kg, specific heat of water c = 42 J / (kg C), specific heat of ice c1 = 21 J / (kg C). The masses of water and ice on the diagram are given in conventional units, showing how many times their masses are less than m = 1 kg. The heat capacity of the calorimeter and heat losses are neglected t, С 1 m / m

4 4. Three in a cube The cube is assembled from the same resistors with resistance R. Three resistors were replaced with ideal jumpers, as shown in the figure. Find the total resistance of the resulting system between pins A and B. Which resistors from the rest can be removed so that this does not change the total resistance of the system? If you know that the amperage that flows through most of the resistors in an electrical circuit is equal, how do you calculate the amperage in the wire connected to node A (or B)? I 2A Calculate the amperage flowing through the ideal jumper AA? 5. Side conveyor A conveyor belt lying on its side moves along a rough horizontal floor so that the plane of the belt is vertical. The speed of the conveyor belt is equal to υ. The conveyor moves along the floor at a constant speed u perpendicular to the main sections of its belt. For some time, the conveyor has shifted to a distance s. Its new position is shown in the figure. The conveyor pushes a block in the shape of a rectangular parallelepiped on the floor. The figure shows a top view of this system. Ignoring the belt deflection and assuming that the movement of the bar is steady, find the displacement of the bar in time s / u. Determine the work of moving the bar performed by the conveyor during this time. The coefficient of friction between the bar and the floor is μ1, and between the bar and the tape μ2.

5 11 class 1. Power in space On a bar of mass m = 2 kg initially resting on a smooth horizontal table, a constant horizontal force F began to act. As a result, the dependence of the power N on the displacement s of the bar was obtained. Some measurements may not be very accurate. In what coordinate axes is the experimental dependence of power on displacement linear? Determine the power of the force at the point with the coordinate s = 1 cm. Find the value of the force F. N, W, 28.4.57.75 1.2 1.1 1.23 1.26 1.5 s, cm 1, 2, 4, 7, "Dark matter" Clusters of stars form collisionless systems of the galaxy, in which the stars move uniformly in circular orbits around the axis of symmetry of the system. Galaxy NGC 2885 consists of a cluster of stars in the form of a sphere (cores with a radius of r = 4 kpc) and a thin ring, the inner radius of which coincides with the radius of the core, and the outer one is equal to 15 r. The ring consists of stars with negligible mass in comparison with the core. In the core, the stars are evenly distributed. It was found that the linear speed of motion of stars in the ring does not depend on the distance to the center of the galaxy: from the outer edge of the ring to the edge of the core, the speed of stars is υ = 24 km / s. This phenomenon can be explained by the presence of non-luminous mass ("dark matter"), distributed spherically symmetrically relative to the center of the galaxy outside its core. 1) Determine the mass Me of the galactic nucleus. 2) Determine the average density ρя of the substance of the galactic nucleus. 3) Find the dependence of the density of "dark matter" ρт (r) on the distance to the center of the galaxy. 4) Calculate the ratio of the mass of "dark matter" affecting the motion of stars in the disk to the mass of the core. Note: 1 kpc = 1 kiloparsec = 3, m, gravitational constant γ = 6, N m 2 kg 2.

6 3. Four in a cube The cube is assembled from identical resistors with resistance R. Four resistors are replaced by ideal jumpers, as shown in the figure. Find the total resistance of the resulting system between pins A and B. Through which resistors the current current is maximum, and through which and minimum? Find these current values ​​if the current entering the node A is equal to I = 1.2 A? What is the current flowing through the ideal jumper AA`? 4. Rhombus. A cyclic process performed over an ideal gas on the (p, V) plane is a rhombus (see the qualitative figure). Vertices (1) and (3) lie on the same isobar, and vertices (2) and (4) lie on the same isochore. During the cycle, the gas performed work A. How much does the amount of heat Q12 supplied to the gas in section 1-2 differ from the amount of heat Q 3.4 in section 3-4 ?, removed from the gas by 5. There are no oscillations! In an electrical circuit (see Fig.), Consisting of a resistor with resistance R, a coil with inductance L, a capacitor with a capacitance of C contains a charge Q. At some point in time, the key K is closed and at the same time begins to change the capacitance of the capacitor so that an ideal voltmeter shows a constant voltage. 1) How does the capacity of the capacitor C (t) depend on time when t changes from to t 1 C L? 2) What work have been done by external forces during time t1? Consider t 1 L / R C L. Hint. The amount of heat released on the resistor during the time t1 is equal to t1 2 2 Q WR I () t Rdt. 3C

11 class 1 Power in space A bar of mass m = kg initially resting on a smooth horizontal table began to act with a constant horizontal force F As a result, a dependence was obtained

The regional stage of the All-Russian Olympiad for Schoolchildren in Physics January 16 g 11 grade 1 Power in space A bar of mass m = kg initially resting on a smooth horizontal table began to act

Regional stage of the All-Russian Olympiad for schoolchildren in physics. January 6, grade 9. Minimum path A car traveling at a speed υ, at some moment starts to move with such a constant acceleration,

1 class 1. Power time As a result of the experiment, the dependence of the power N of a constant horizontal force on the time t of its action on the initially resting on a smooth horizontal force was obtained.

Grade 11 1. Density of oxygen Find the density of oxygen at a pressure of param1 kPa and a temperature of param2 K. Consider the gas ideal. param1 50 150 200 300 400 param2 300 350 400 450 500 2. Power in the circuit

Grade 7 1. A coil of copper wire has a mass of 360 g. Find the length of the wire in a coil if the cross-sectional area of ​​the wire is 0.126 mm 2, and 1 cm 3 of copper has a mass of 8.94 g. Express the answer in meters and

IV Yakovlev Materials on physics MathUs.ru Open Olympiad Phystech-Lyceum 2015 Physics, grade 11 1. On a thin transparent horizontal table lies a thin converging lens with a focal length F = 70

The first (qualifying) stage of the academic competition of the Olympiad of schoolchildren "Step into the Future" in the general subject "Physics", Autumn 05, Option Z AND A CH A. The body moves in the first half of the time

Grade 9 Schoolboy Petya Ivanov from the six wires at his disposal assembled the circuit shown in Fig. 1. Find the resistance of the circuit between points A and D, if the resistances of wires AB and BD are equal

Grade 11. Round 1 1. Problem 1 A cylindrical washer, sliding on smooth ice at a speed, experienced a frontal elastic collision with a stationary cylindrical washer of a different mass. After the collision, the first

Interregional subject Olympiad of Kazan Federal University on the subject "Physics" Grade 9. Option 1. 2014-2015 academic year, Internet tour 1. (1 point) Boy Petya the first half of the way from school

IV Yakovlev Materials on physics MathUs.ru Phystech Olympiad in physics Grade 11, online stage, 2013/14 1. A stone thrown from the roof of the shed almost vertically upward at a speed of 15 m / s fell to the ground

Bank of tasks in physics Grade 1 MECHANICS Uniform and uniformly accelerated rectilinear motion 1 The figure shows a graph of the dependence of the coordinates of a body on time during its rectilinear motion along the x-axis.

Olympiad named after J. Cl. Maxwell Regional Stage January 6th grade 7. Where is the density here? The laboratory carried out measurements of the mass and volume of five bodies made of four materials: birch, ρ B =, 7

Paragraphs 88-93 repeat exercise 12. Perform the test Option 3679536 1. Task 1 The figure shows the graphs of the dependence of the speed module of four cars on time. One of

Minsk City Olympiad PHYSICS 2002 11th grade. 1. The rotor of the electric motor model is a rectangular frame with area S, containing n turns of wire, fixed on a massive base,

Ministry of Education and Science of the Perm Territory Physics Tasks of the municipal stage of the All-Russian Olympiad for schoolchildren in the Perm Territory 2017/2018 academic year.

MOSCOW OLYMPIAD OF SCHOOLBOYS IN PHYSICS 2016 2017 academic year ZERO TOUR, CORRESPONDENCE TASK. Grade 11 The attached file contains the November correspondence assignment for the 11th grade. Prepare some sheets

Grade 10. Option 1. 1. (1 point) The rotational speed of the propeller of a light-engine aircraft is 1500 rpm. How many revolutions will the propeller have time to make on the way of 90 km at a flight speed of 180 km / h. 1) 750 2) 3000 3)

Physics. In the calculations, take: m Gravity acceleration g 10 s Universal gas constant J R 8.31 mol K Avogadro constant N A 6, 0 10 mol 3 1 Planck constant h 34 6.63 10 J s 1 F Electric

MOSCOW STATE TECHNICAL UNIVERSITY NAMED AFTER NE BAUMAN THE FINAL STAGE OF THE OLYMPIAD "STEP INTO THE FUTURE" ON THE COMPLEX OF SUBJECTS "EQUIPMENT AND TECHNOLOGY"

Kurchatov 2018, physics, qualifying stage 11 grade Hydrostatics Problem 1.1 A cube with a side a = 10 cm floats in mercury, submerged by 1/4 of its volume. Water is gradually added over the mercury until

The final (full-time) stage of the All-Siberian Olympiad in Physics Problems 9 grades. (March 29, 2009) 2R m 3R 1. A massive homogeneous chain with a mass of mass m at one end is thrown over a block of radius R and is located

The attached file contains the November correspondence assignment for the 11th grade. Prepare several sheets of paper in a cage, on which hand-write detailed solutions of the attached problems. Take a picture of the pages

The first (qualifying) stage of the academic competition of the Olympiad of schoolchildren "Step into the Future" in the general subject "Physics", autumn 016. Option 1 1. The disc rolls without slipping along the horizontal

Rigid body dynamics. 1. A thin homogeneous rod AB of mass m = 1.0 kg moves translationally with acceleration a = 2.0 m / s 2 under the action of forces F 1 and F 2. Distance b = 20 cm, force F 2 = 5.0 N. Find the length

9F Section 1. Concepts, definitions Insert the missing words: 1.1 A body can be considered a material point only if 1.2 If at any moment of time all points of the body move in the same way, then such

IV Yakovlev Materials on physics MathUs.ru Open Olympiad Phystech-Lyceum 2015 Physics, grade 9 1. The mass to the brim of a filled test tube with water M 1 = 160 g. After a piece of metal is placed in it

I. V. Yakovlev Materials on physics MathUs.ru Gravitation Problem 1. (MIPT, 1987) How fast the plane would have to fly along the equator so that the force of pressure of the seated passengers on the aircraft seats would decrease

Final annual test in physics Grade 10 1 Option Part A A1. On a ring road L = 15 km long, a truck and a motorcycle are traveling in one direction at speeds V1, respectively

OLYMPIAD FOR PUPILS "STEP INTO THE FUTURE" Complex of subjects "TECHNOLOGY AND TECHNOLOGY" MATERIALS OF OLYMPIAD TASKS 008-009 I. Scientific and educational competition TASKS ON MATHEMATICS Solve the system of equations

Lesson 11 Final 2. Mechanics. Problem 1 The figure shows a graph of the dependence of the cyclist's path S on time t. Determine the time interval after the start of the movement when the cyclist moved with

Class 11 Ticket 11-01 Code 1. A system of three bars on a horizontal table is set in motion by applying a horizontal force F (see fig.). Coefficient of friction between the table and the bars

Physics, grade 9 (grade 10 - 1 semester) Option 1 1 According to the graph of the dependence of the speed modulus on time, shown in the figure, determine the modulus of acceleration of a rectilinearly moving body at the moment of time

Deferred tasks (25) In the area of ​​space where there is a particle with a mass of 1 mg and a charge of 2 10 11 C, a uniform horizontal electric field is created. What is the strength of this field, if from

Minsk Regional Olympiad for Schoolchildren in Physics 2000 11th grade. 1. Two washers of masses m and 2m, connected by a weightless thread of length l, lie on a smooth horizontal surface so that the thread is fully stretched.

Grade 9 Problem. Falling icicles. An icicle came off the roof of the house and in t = 0.2 s flew past a window, the height of which was h = .5 m. From what height h x, relative to the upper edge of the window, did it come off? Sizes

IV Yakovlev Materials on physics MathUs.ru Open Olympiad Phystech-Lyceum 2015 Physics, grade 10 1. A sealed vessel is divided into two compartments with a heat-insulating partition, in which a small

Grade 10. Option 1 1. The body slides off an inclined plane with an angle of inclination = 30 о. On the first k = 1/3 of the way the coefficient of friction is 1 05 ,. Determine the coefficient of friction for the remaining segment of the path, if at the base

Option 2805281 1. The boy slides down the snow slide with uniform acceleration. The speed of the sleigh at the end of the descent is 10 m / s. The acceleration is 1 m / s 2, the initial speed is zero. How long is the slide? (Give the answer

Tula State University. Physics Olympiad February 6. A cylinder of radius R = cm is sandwiched between two horizontal surfaces that move in different directions with speeds v = 4 m / s

ALL-RUSSIAN OLYMPID OF SCHOOLCHILDREN IN PHYSICS. 017 018 account MUNICIPLE ETP. 10 KLSS 1. Two balls are thrown simultaneously towards each other with the same initial velocities: one from the ground

Administrative work for the 1st half of the year Option 1. Part 1 A1. The graph shows the dependence of the speed of a rectilinearly moving body on time. Determine the acceleration modulus of the body. 1) 10 m / s 2 2) 5 m / s

The first (qualifying) stage of the academic competition of the Olympiad of schoolchildren "Step into the future" in the educational subject "physics", autumn 05 g Option 5

Olympiad tasks 2014/2015 academic year Grade 9 Option 1 1. A cube of density ρ 1 is held in equilibrium by a weightless spring under an inclined wall, the angle of inclination of which is α, in a fluid with density ρ 2> ρ

Year 216 Class 9 Ticket 9-1 1 Two weights of masses m and located on a smooth horizontal table are tied with a thread and connected to a load of 3m by another thread thrown over a weightless block (see fig) by friction

Typical version of the academic competition of the Olympiad of schoolchildren "Step into the future" in the general subject "Physics" PROBLEM 1. A point moves along the x-axis according to the law of the speed of a point at t = 1 s.

Task 1 A cylindrical vessel, into which a liquid is poured, was closed with a sealed lid and began to move vertically downward with an acceleration of 2.5 g. Determine the fluid pressure on the vessel lid, if in a stationary

2.1. The calorimeter contained ice at a temperature t 1 = -5 C. What was the mass m 1 of ice if, after adding m 2 = 4 kg of water to the calorimeter, having a temperature of t 2 = 20 C, and establishing thermal equilibrium

MOSCOW STATE TECHNICAL UNIVERSITY NAMED AFTER NE BAUMAN THE FINAL STAGE OF THE OLYMPIAD "STEP INTO THE FUTURE" ON THE COMPLEX OF SUBJECTS "EQUIPMENT AND TECHNOLOGY"

Ticket N 5 Ticket N 4 Question N 1 A horizontal force begins to act on a body with a mass of m 2.0 kg, the modulus of which is linearly dependent on time: F t, where 0.7 N / s. Friction coefficient k 0.1. Determine the moment

Establishing correspondence, part 2

Complex Olympiad for schoolchildren "Akademika" [email protected] 1. The initial speed of a stone thrown at a certain angle to the horizon is 10 m / s, and after a time of 0.5 s the speed of the stone is 7 m / s. On

Task 1 Choose what is the orientation of the image of the object "b" in the flat mirror "a" (see Fig.). a 45 0 b a b c d e Task 2 The amount of heat Q was transferred to a body of mass m and specific heat c. Temperature

Ticket N 5 Ticket N 4 Question N 1 Two bars with masses m 1 = 10.0 kg and m 2 = 8.0 kg, connected by a light inextensible thread, slide along an inclined plane with an angle of inclination = 30. Determine the acceleration of the system.

Republican Subject Olympiad District (City) Stage Physics First Name Last Name School 1 The exam duration is 180 minutes 4 incorrect answers take points for 1 correct answer 3 Each question

Belarusian Republican Olympiad in Physics (Gomel, 1998) Grade 9 9.1 To study the elastic properties of rubber, a rubber band was suspended vertically, and various

Part 1 Answers to tasks 1 4 are a digit, a number or a sequence of numbers. Write down the answer in the answer field in the text of the work, and then transfer it to ANSWER FORM 1 to the right of the number of the corresponding task,

Tasks B2 in physics 1. The spring pendulum was taken out of the equilibrium position and released without initial speed. How do the following physical changes during the first quarter of the oscillation period of the weight of the pendulum

Phystech Olympiad in Physics Class 9 Ticket - Code (to be filled in by the secretary) 3. The gun is installed on a flat mountain slope forming an angle with the horizon. When fired "up" on the slope, the projectile falls on the slope

Phystech Olympiad in Physics Class 8 Ticket - Code (filled in by the secretary) A system of three bars located on a horizontal table is set in motion by applying a horizontal force (see Fig.) Coefficient

1 Kinematics 1 Material point moves along the x-axis so that the time coordinate of the point x (0) B Find x (t) V x At At the initial moment, the Material point moves along the x-axis so that ax A x B is the initial

Lesson 7 The laws of conservation Task 1 The figure shows the graphs of the change in the speeds of two interacting trolleys of different masses (one trolley catches up and pushes the other). What information about carts

Explanation of the phenomena 1. The figure shows a schematic view of the graph of changes in the kinetic energy of a body over time. Choose two correct statements describing the movement in accordance with the given

IV Yakovlev Materials on physics MthUs.ru Electromagnetic induction Problem 1. A wire ring of radius r is in a uniform magnetic field, the lines of which are perpendicular to the plane of the ring. Induction

Grade 9. Option 1. The body was thrown horizontally from the tower. Through t = s, its speed increased by k = 3 times. With what speed V0 was the body thrown? Body speed varies with time as For a given

Grade 7 1. How many times per day do the hour and minute hands of the clock lie on one straight line? 2. The weight of an empty canister is 200 g, and a canister filled with kerosene is 5 kg. How many liters of kerosene are in a canister?

I. V. Yakovlev Materials on physics MathUs.ru Contents Friction force 1 All-Russian Olympiad for schoolchildren in physics ................... 1 2 Moscow Physics Olympiad ...... ..................... 3 3 MIPT

Results of the municipal stage of the All-Russian Olympiad for schoolchildren in physics 2012-2013 academic year Analysis of the results of the municipal stage of the Olympiad 1 task. Grade 9 Experimenter Glitch from the balcony observes

Instructions for tasks # 1_45: These tasks ask questions and give five expected answers, only one of which is correct. Find the number corresponding to this task in the answer sheet, find

Solutions and evaluation criteria Problem 1 A wooden cylinder floats in a cylindrical vessel with water, as shown in Fig. 1, protruding at a = 60 mm above the liquid level, which is equal to h 1 = 300 mm. To the top

LYCEUM 1580 (AT MSTU named after N.E. Bauman) DEPARTMENT "FOUNDATIONS OF PHYSICS", CLASS 11, 3 SEMESTER 2018-2019 SCHOOL YEAR Option 0 Problem 1. Slurry weeding ring of area S = 100 cm. 2 - having resistance R = 0 , 01

For the development of students' creative abilities, problems of solving DC resistor circuits by the method of equipotential nodes are of interest. The solution to these problems is accompanied by a sequential transformation of the original circuit. Moreover, it undergoes the greatest change after the first step, when this method is used. Further conversions are associated with the equivalent replacement of series or parallel resistors.

To transform the chain, they use the property that in any chain points with the same potentials can be connected into nodes. And vice versa: the nodes of the chain can be divided, if after that the potentials of the points included in the node do not change.

In the methodological literature, they often write as follows: if the circuit contains conductors with the same resistances located symmetrically relative to any axis or plane of symmetry, then the points of these conductors, symmetrical about this axis or plane, have the same potential. But the whole difficulty is that no one on the diagram designates such an axis or plane, and it is not easy to find it.

I propose another, simplified way to solve such problems.

Problem 1... A wire cube (fig. 1) is included in the chain between the points A to B.

Find its total resistance if the resistance of each edge is R.

Put the cube on the edge AB(fig. 2) and "cut" it into twoparallel halves plane AA 1 B 1 Bpassing through the lower and upper ribs.

Consider the right half of the cube. We will take into account that the lower and upper ribs split in half and became 2 times thinner, and their resistances increased 2 times and became 2 times R(fig. 3).

1) Find resistanceR 1the top three conductors connected in series:

4) Find the total resistance of this half of the cube (Fig. 6):

We find the total resistance of the cube:

It turned out to be relatively simple, understandable and accessible to everyone.

Task 2... The wire cube is connected to the chain not by an edge, but by a diagonal AS any facet. Find its total resistance if the resistance of each edge is R (fig. 7).

Place the cube on edge AB again. We "cut" the cube into twoparallel halvesthe same vertical plane (see Fig. 2).

Consider again the right half of the wire cube. We take into account that the upper and lower ribs are split in half and their resistances are 2 R.

Taking into account the condition of the problem, we have the following connection (Fig. 8).

Transcript

1 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. Part I. Calculation of resistances Ohm's law. Resistance. Serial and parallel connection, balanced circuits. Bridges. Star-delta transformation. Jumper chains. Endless chains and meshes .. Determine the equivalent resistance of the wire structures shown in the figure. The resistance of each link in the structure, i.e. the wire between the knots, regardless of the length, is equal. a) b) c) d) e) f) d) 2. N points are connected to each other by identical conductors with resistance each. Determine the equivalent circuit resistance between two adjacent points. 3. In a Wheatstone bridge, the resistances are selected so that the sensitive galvanometer reads zero. a) Assuming the resistances, 2 and r are known, determine the value of the resistance rx. b) if you swap the battery and the galvanometer, you get a bridge circuit again. Will the balance be maintained in the new scheme? 4. Find the equivalent resistance of the section of the circuit. a) 2 b) 2 c) Determine the equivalent resistance of the circuit section containing jumpers with negligible resistance. a) b) The electrical circuit is made up of seven series-connected resistors = kΩ, 2 = 2 kΩ, 3 = 3 kΩ, 4 = 4 kΩ, 5 = 5 kΩ, 6 = 6 kΩ, 7 = 7 kΩ and four jumpers. The input is supplied with voltage U = 53.2 V. Specify the resistors through which the minimum and maximum currents flow, and determine the values ​​of these currents.

2 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 7. A circuit consisting of three resistors and four identical jumpers (the lower two are connected in parallel) is connected to a source with a voltage of U = 0 V. Considering the known = 3 ohms, determine the current in the jumper B. The resistance of the jumpers is much lower than the resistance of the resistors. U 2 V 8. The cube is assembled from the same resistors with resistance. The two resistors are replaced with ideal jumpers as shown in the figure. Find the total resistance of the resulting system between the contacts and B. What resistors from the rest can be removed, and this will not change the total resistance of the system? If it is known that I = 2 current flows through most of the resistors in the circuit, what is the total current entering the system at the node? What current flows through an ideal jumper `? `K M C L B B` 9. Determine the resistance of the wire mesh between the indicated terminals. The thick line has negligible resistance. The resistance of each of the other mesh links is equal. 0. Determine the equivalent resistance of the semi-infinite resistor chains shown in the figure. 2 2 a) b) c) Determine the equivalent resistance of an infinitely branching chain consisting of resistors with resistance. 2. Endless square mesh mesh is made of wire. The resistance of each edge of the mesh is equal. In Figure C, the middle of rib B. It is known that when you connect an ohmmeter between points and B, it shows resistance / 2. What resistance will the ohmmeter show when connected between points and C? 3. Determine the resistance of infinite flat grids with the resistance of one side of the cell, measured between the nodes and B. a) b) c) C C C 4. Determine the resistance of an infinite volumetric cubic grid with the resistance of one side of the cell, measured between adjacent nodes and B.

3 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 5. The hollow metal ball has a radius r = 0 cm and a wall thickness d = mm. It is made of copper, except for the strip at the "equator" with a width of a = 2 mm, which is made of aluminum. When the voltage U = 0, mV was applied to the "poles" of the ball, a current I = 5.2 went through it. The experiment was repeated with another ball, which had an iron one instead of an aluminum strip. What current will go through this ball? The specific resistance of aluminum is 0.03 ohm mm 2 / m, iron is 0.0 ohm mm 2 / m. 6. A ring of radius r = 0 cm is made of wire with a cross section of S = 5 mm 2. The material of the wire is inhomogeneous and its resistivity depends on the angle φ as shown in the graph. The resistance between all possible pairs of points in the ring is measured with an ohmmeter. What is the maximum resistance that can be obtained with such measurements?

4 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. Measurements of current and voltage. meter, voltmeter and ohmmeter. Part II Measuring instruments Determine the unknown parameters of the electrical circuit. (Devices are considered ideal). U 0 2 a) U 0 = 24 B = 2 I -? U v-? b) 2 U I 4 = = 2 2 = 3 3 = 2 4 = 20 5 = 0 U-? I 6 =? 2. Determine the ammeter reading in the circuit shown. Source voltage U =, 5 V, resistance of each resistor = com. 3. On the section of the circuit, the diagram of which is shown in the figure, resistors with resistances = 6 Ohm, 2 = 3 Ohm, 3 = 5 Ohm, 4 = 8 Ohm are connected. Readings of the first ammeter I = 0 ,. Find the reading on the second ammeter. 4. On the basis of the known readings of the devices, determine the unknown ones. Consider the resistances of the ammeters much less than the resistance of the resistors. The devices are the same. 6 a) b) c) C 5 B 5 2 3C d) e) B How will the readings of ideal instruments change when the rheostat / potentiometer slider is moved in the direction indicated by the arrow or when the key is opened? 3 a) b) c) d) Ɛ, r Ɛ, r 6. The circuit is assembled from a number of different resistors, a rheostat, an ideal battery, a voltmeter and an ammeter. The rheostat slider is shifted, slightly increasing its resistance. In which direction will the readings of the voltmeter and ammeter change?

5 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 7. Determine the readings of the voltmeter connected between the two nodes of the fragment of the electrical circuit, if the readings of the ammeters and 3 are equal to I = 2, I3 = 9, respectively, and the resistance of the resistors = 0 Ohm. I2 I3 I 8. An electric circuit in the form of a tetrahedron contains four identical resistors, an ideal constant voltage source and an ideal ammeter that shows the current I = 2. If you replace the ammeter with an ideal voltmeter, it will show a voltage U = 2 V. Determine the voltage U0 of the source and resistance of one resistor. 9. The electrical circuit is a grid consisting of identical links with the same resistance. One of the links has been replaced with an ideal voltmeter. The circuit is supplied with voltage U0 = 9.7 V. Find the reading on the voltmeter. U0 0. The electrical circuit is a grid consisting of identical links with the same resistance. One of the links has been replaced with an ideal voltmeter. The voltage U0 = 73 V is applied to the circuit. Find the voltmeter reading. U0. The experimenter assembled the circuit shown in the figure from several identical resistors and identical voltmeters. What will be the sum of the readings of all voltmeters if a voltage U = 6 V is applied to the B contacts. The resistance of the voltmeters is much greater than the resistance of the resistors. 2. The section of the circuit consists of unknown resistances. How, having a source, an ideal ammeter and voltmeter, connecting wires with zero resistance, measure the resistance connected to points A and B without breaking a single contact in the circuit? WCK В NDCLEDFG 3. Physics connoisseur assembled a circuit of three identical resistors, connected it to a constant voltage source (which can be considered ideal) and measured the voltage with a voltmeter first between points and D, and then between points and B. He got U = 3 V and U2 = 0.9 V, respectively. Then the physics connoisseur connected points and C with a wire (whose resistance can be neglected) and measured the voltage between points B and D. What did he get? 4. The circuit shown in the figure contains 50 different ammeters and 50 identical voltmeters. The readings of the first voltmeter U = 9.6 V, the first ammeter I = 9.5 m, the second ammeter I2 = 9.2 m.Determine from these data the sum of the readings of all voltmeters. 5. If only the first voltmeter is connected to the battery, then it shows 4 V. If only the second is connected, then it shows 4.5 V. If both of these voltmeters are connected in series to the battery, then together they show 5 V. What will the readings of these two voltmeters be if they are connected to the same battery in parallel? 2 B

6 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 6. The electrical circuit consists of two identical voltmeters and two ammeters. Their readings are U = 0 V, U2 = 20 V, I = 50 m, I2 = 70 m, respectively. Determine the resistance of the resistor, having received the general answer. 7. The electrical circuit consists of a battery, six resistors, the resistance values ​​of which are = Ohm, 2 = 2 Ohm, 3 = 3 Ohm, 4 = 4 Ohm, and three identical ammeters, the internal resistance r of which is small. Calculate the ammeter readings if the battery voltage is U = 99 V. 8. Find the readings of the same voltmeters. The resistances of voltmeters are much higher than the resistances of the resistors = 0 ohms. Input voltage U = 4.5 V. 9. An ammeter and a voltmeter are connected in series to a battery with an EMF Ɛ = 9 V and an unknown internal resistance. The resistances of the devices are unknown. If a resistance is connected in parallel with the voltmeter (its value is also unknown), then the ammeter reading doubles, and the voltmeter reading is halved. What was the voltmeter reading after connecting the resistance? 20. Determine the readings of the same ohmmeters in the circuits shown in the figure. The resistance of each of the resistors in the circuits is equal. a) b) c) 2. The electric circuit is a grid consisting of identical links with the same resistance. Two of the links are replaced with identical ohmmeters. Find ohmmeter readings. 22. Determine the sum of the ohmmeter readings in the diagram shown in the figure. Ɛ, r Ɛ 2, r The circuit shown in the figure was assembled from identical ohmmeters. One of the instruments shows resistance = 2000 ohms. Determine the sum of the readings of the two remaining ohmmeters. 24. Build a graph of the dependence of the readings of the right ohmmeter depending on the resistance of the rheostat, which can vary from 0 to 2. Own resistance of the ohmmeter. Consider the ohmmeters the same. 0-2

7 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. Part III. Power sources. Nonlinear elements Joule-Lenz law. Sources of tension. The electromotive force of the current source. Ohm's law for a complete circuit. Power supply connections. Non-linear elements .. The circuit shown in the figure is assembled from identical bulbs and connected to a voltage source. Arrange the bulbs in ascending order of brightness. 2. A four-resistor circuit is connected to the regulated voltage source as shown in the figure. The meter shows a current of 2.5. On two resistors, a power of 50 W is allocated, on the other two 200 watts. Key K is closed, and the source voltage is changed so that the ammeter again reads 2.5. What power will be allocated on the resistors after that? 3. A chain of two series-connected resistors is connected to a constant voltage source U = 2 V. Resistance of one of them = 4 ohms. At what value of resistance 2 of the second resistor will the thermal power released on it be maximum? Find this maximum power. 4. There are the same resistors in the shape of a regular cylinder. The side surface of each resistor is well insulated, and when it is heated, heat transfer occurs only through the ends. One of the resistors was connected to an ideal battery. At the same time, it heated up to a temperature of t = 38 C. Then, three such resistors were connected in series to this battery, tightly matching their ends and ensuring good electrical contact. To what temperature will the resistors heat up? Room temperature t0 = 20 C. The heat transfer power is proportional to the temperature difference between the resistor and the environment. The resistance of the resistors does not change when heated. 5. A cylindrical conductor of radius r consists of two homogeneous sections with resistivities ρ and ρ2 and an inhomogeneous section of length L connecting them. What heat power is released in an inhomogeneous section if the voltage on ρ ρ 2 2r unit length of a conductor with resistivity ρ is equal to u and L the resistivity of the inhomogeneous section varies linearly from ρ to ρ2? 6. A resistor is connected to the ideal current source. The source voltage is equal to U. It turned out that the temperature of the resistor T depends on the time t as T = T0 + αt (T0 and α are known constants). The resistor has mass m and is made of a substance with specific heat c. What is the thermal power given off by the resistor to the environment? 7. The resistance of the resistor increases linearly with temperature, and the power of heat transfer from its surface is directly proportional to the temperature difference between the resistor and the environment. If a very small current is passed through the resistor, its resistance is 0. When the amount of current flowing through the resistor approaches I0, the resistor quickly heats up and melts. What is the voltage across the resistor if a current I0 / 2 is passed through it? 8. A current source is connected to a resistor, the resistance of which depends on temperature according to the law (t) = 0 (+ αt), where t is the temperature in С, α and 0 are unknown coefficients. After a while, the source is disconnected from the resistor. The graph of the resistor temperature versus time is shown in the figure. The heat transfer power of the resistor to the environment is proportional to the temperature difference between the resistor and the environment: P = βt, where β is an unknown coefficient. Assuming that the temperature of the resistor is the same at all points, find α.

8 Cannot display the pattern at this time. Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 9. Find the EMF and internal resistance of the equivalent source (Ɛe = φ φb) Ɛ Ɛ 2 a) b) c) 2r r B 2 r B Ɛ Ɛ r d) e) r f) 2Ɛ BB Ɛ Ɛ r Ɛ 2 Ɛ r B Ɛ r 2Ɛ Ɛ B r 0. There is a circuit containing N = 000 identical current sources with EMF Ɛ and internal resistance r each. There are m current sources between points ub (on the SV arc). Find the potential difference between the points and B. What will this potential difference be if the elements are facing each other with the same poles ?. The experimenter assembled an electrical circuit consisting of different batteries with negligible internal resistances and identical fuses, the resistance of which is also very small, and drew its diagram (the fuses in the diagram are indicated by black rectangles). The experimenter remembers that on that day during the experiment, all the fuses remained intact. Some battery voltages are known. Reconstruct unknown voltage values. 2. The figure shows the idealized current-voltage characteristics of the diode and resistor. Plot the current-voltage characteristic of the circuit section containing a diode and a resistor connected: a) in parallel; b) consistently. I0 0 I U0 2U0 D U 3. The figure shows the idealized current-voltage characteristics of the diode and resistor. Plot the current-voltage characteristic of the section of the circuit containing the diode and two resistors. -0.4-0.2 3.0 2.0.0 0 -, 0 I, D 0.2 0.4 0.6 U, V a) b) 4. The figure shows the current-voltage characteristics of the resistor and the circuit section consisting of a resistor and a nonlinear element connected: a) in series; b) in parallel. -0.4-0.2 3.0 2.0.0 0 I, Σ 0.2 0.4 0.6 U, V Plot the current-voltage characteristic of the nonlinear element. -, 0 0.5 5. Determine through which nonlinear element the greater current will flow, 2 0.4 if it is connected to a source with U0 = 0.5 V and r = Ohm. 3 0.3 0.2 I, 0, 0 0, 0.2 0.3 0.4 0.5 0.6 U, V

9 Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year. 6. Find the amount of current flowing through the diode in the circuit shown in the figure. The voltage of the ideal source U and the resistance are known. 4 U 2 7. A nonlinear element x is connected to one of the bridge arms, for which the dependence of the current Ix on the applied voltage Ux is given by the formula: ix = Ux 3, where = 0.25 / V 3. Find the power Nx released on the nonlinear element under the conditions when there is no current through the galvanometer Г. Resistances of the rest of the bridge arms = 2 ohms, 2 = 4 ohms and 3 = ohms. 8. When a light bulb was inserted into the table lamp, on which the power W = 60 W was dissipated, it turned out that the power W2 = 0 mW was dissipated on the connecting wires of the lamp. What power will be dissipated on the connecting wires if you put a light bulb with a power of W3 = 00 W? The voltage in the network in both cases is considered equal to U = 220 V. 9. The resistance of the element X changes depending on the voltage across it. If the voltage U< Uкр, то сопротивление равно, а при U >Ucr resistance is 2. From three elements X, the circuit shown in the figure is assembled. Find the dependence of the current through the circuit on the voltage across it. 20. The voltage of a source connected to a circuit consisting of identical resistors with resistance = Ohm and a non-linear element can be changed. The dependence of the ammeter readings on the source voltage is given on the graph. The positive direction of the current is specified in the circuit diagram. Reconstruct the current-voltage characteristic of the nonlinear element from this data. 2. The electrical circuit, the diagram of which is shown in the figure, contains three identical resistors = 2 = 3 = and three identical diodes D, D2, D3. The current-voltage characteristic of the diode is shown in the graph. Determine the current through the ammeter I depending on the voltage UВ between the points and V. The meter is ideal. Plot the dependence of I on UB, indicating the values ​​of the current and voltage at the characteristic points. 22. You have an unlimited number of arbitrary resistors and diodes at your disposal. Diodes pass current only in one direction, while the voltage drop across them is equal to V (see Fig. A). Which circuit needs to be assembled so that it has such a dependence of current on voltage, as shown in Fig. b? Try to use as few elements as possible. Test. D.C. to 0 Ohm (on one of the parallel-connected resistors) 2. 3/30

10 3. 0 / m 5. 4 m Talent and Success Foundation. Sirius educational center. Direction "Science". pretty physical change. 207 year.

Electricity. D.C. Kirchhoff Problem 1. The electrical circuit (see figure) consists of two identical voltmeters and two ammeters. Their readings: U 1 = 10.0 V, U 2 = 10.5 V, I 1 = 50 ma, I 2 =

I. V. Yakovlev Materials on physics MathUs.ru Contents Electrical circuits 1 All-Russian Olympiad for schoolchildren in physics ................... 1 2 Moscow Physics Olympiad ...... .....................

Master class “Electrodynamics. D.C. Work and power of current ". 1. A constant electric current flows through the conductor. The amount of charge passing through a conductor increases over time.

1 Direct electric current Reference information. DEFINITION OF THE CURRENT FORCE Let a charge q pass through some surface, the area of ​​which is S, perpendicular to it. Then the current strength is called

Option 1 Initial level 1. The figure shows a graph of the dependence of the current in the conductor on the voltage at its ends. What is the resistance of the conductor? A. 8 Ohm. B. 0.125 ohm. B. 16 Ohm. G. 2 Ohm.

C1.1. The photo shows an electrical circuit consisting of a resistor, a rheostat, a key, a digital voltmeter connected to a battery, and an ammeter. Using the laws of direct current, explain how

The figure shows a DC circuit. The internal resistance of the current source can be neglected. Establish a correspondence between physical quantities and formulas by which they can be calculated (

Task 12. 1. The figure shows a diagram of an electrical circuit consisting of three resistors and two keys K1 and K2. A constant voltage is applied to points A and B. The maximum amount of heat released

IV Yakovlev Materials on physics MathUs.ru Nonlinear elements The current-voltage characteristic of a nonlinear element of an electric circuit is a nonlinear function. Problem 1. (All-Russian., 1993, final, 9)

IV Yakovlev Materials on physics MathUs.ru Calculation of resistance Problem 1. ("Kurchatov" 016, 8) There are two pieces of copper wire of the same cross-section in the laboratory. The resistance of these pieces,

189 1) In each node of the circuit, the sum of the incoming currents is equal to the sum of the outgoing currents, in other words, the algebraic sum of all currents in each node is equal to zero. 2) In any closed loop, arbitrarily chosen

Option 1 1. The current in the conductor increases uniformly from 0 to 3 A for 10 s. Determine the charge that has passed in the conductor during this time. Answer: 15Cl. 2. Three batteries of accumulators with EMF 12 V, 5 V and 10

1. The current in the conductor increases uniformly from 0 to 3 A for 10 s. Determine the charge that has passed in the conductor during this time. Answer: 15Cl. 2. Three batteries of accumulators with EMF 12 V, 5 V and 10 V and the same

Ural Federal University named after the first President of Russia B.N. Yeltsin Specialized Educational and Scientific Center Summer School 2019 Physics Analysis of problems and test criteria Task 1. Find resistance

Lesson 19 Direct current. Connections of conductors Task 1 The transfer of matter occurs when an electric current passes through: 1) Metals and semiconductors 2) Semiconductors and electrolytes 3) Gases

In the diagram in the figure, the resistance of the resistor and the impedance of the rheostat are equal to R, the EMF of the battery is equal to E, its internal resistance is negligible (r = 0). How they behave (increase, decrease, remain

Pending References (69) The total resistance of the circuit shown in the figure is 9 ohms. The resistances of the resistors R 1 and R 2 are equal. What is the resistance of each resistor? 1) 81 ohm 2) 18 ohm 3)

IV Yakovlev Materials on physics MthUs.ru Kirchhoff rules In the article “EMF. Ohm's law for a complete circuit ”, we derived Ohm's law for an inhomogeneous section of a circuit (that is, a section containing a current source): ϕ

C1.1. The figure shows an electrical circuit consisting of a galvanic cell, rheostat, transformer, ammeter and voltmeter. At the initial moment of time, the rheostat slider is set in the middle

Physics 8.1-8.2. An approximate bank of tasks Part 1. Direct current 1. The figure shows a section of an electrical circuit through which current flows. Which conductor has the smallest current? 1) 1 2) 2 3) 3 4) 4

"DC LAWS". Electric current is called the ordered directional movement of charged particles. For the existence of a current, two conditions are necessary: ​​The presence of free charges; The presence of an external

Intermediate level Solve orally Assignments on the topic "Calculation of electrical circuits" 8 grade 5 .. Resistors with a resistance of 5 ohms and 0 ohms are connected once in series, the other - in parallel. In which case their

LABORATORY WORK 5 MEASURING THE RESISTANCE OF CONDUCTORS Purpose of the work: studying methods of measuring resistances, studying the laws of electric current in circuits with series and parallel connection

IV Yakovlev Materials on physics MathUs.ru Self-induction Let an electric current I flow through the coil and change with time. An alternating magnetic field of current I generates a vortex electric field,

Tasks 15 in physics 1. An electrical circuit consists of a constant voltage source with EMF = 40 V and an internal resistance r = 2 Ohm, a variable resistance resistor and an ammeter. Which of the following

Irkutsk State Technical University Department of General Education Physics Laboratory work 3.3. "Determination of unknown resistances using a bridge circuit" Assoc. V. I. Schepin

Measurement of power and work of current in an electric lamp. Purpose of work: To learn how to determine the power and work of the current in the lamp. Equipment: Power supply, key, ammeter, voltmeter, lamp, stopwatch. Stroke

PHYSICIAN, grade 11, UMK 2 Option 1, October 2012 Regional diagnostic work in PHYSICS Option 1 Part 1 When completing tasks 1 7 in the answer form 1 under the number of the task being performed, put an "x"

Constant electric current. Current strength Constant electric current. Voltage Ohm's law for a section of a circuit Electrical resistance. Substance resistivity Electromotive force. Internal

I. V. Yakovlev Materials on physics MathUs.ru Current power Problem 1. ("Kurchatov", 2017, 8) Using an electric motor, a load weighing 50 kg is lifted up. In this case, the load moves at a constant speed of 3.5 cm / s.

Yulmetov A.R. Constant electric current. Electrical measurements Methodical instructions for laboratory work Table of contents P3.2.4.1. Ammeter as an ohmic resistance in a circuit .............

Pdf - file pitf.ftf.nstu.ru => Teachers => I.I. Sukhanov Laboratory work 11 Studying the operation of a direct current source The purpose of work for a circuit "current source with load" is experimentally obtained

Physics test 1 option A1. If, at a constant voltage at the ends of the conductor, the resistance of the conductor is doubled, then the current in the conductor 1) will not change 3) it will decrease 2 times 2) it will increase

I. V. Yakovlev Materials on physics MathUs.ru Contents Electrical circuits 1 All-Russian Olympiad for schoolchildren in physics ................... 1 2 Moscow Olympiad for schoolchildren in physics .... ................

Moscow Institute of Physics and Technology Equivalent transformations of electrical circuits. Methodological guide for preparation for the Olympiads. Compiled by Egor Vadimovich Parkevich Moscow 2014 Introduction. In electrical engineering

IV Yakovlev Materials on physics MathUs.ru Current power Problem 1. Resistors with resistances 2R and 3R are connected in series and connected to a constant voltage source U. Find the power released

DC 2008 The circuit consists of a current source with an EMF of 4.5V and an internal resistance of r =, 5 ohms and conductors with a resistance of 4.5 ohms and 2 = ohms The work done by the current in the conductor in 20 minutes is equal to r ε

IV Yakovlev Materials on physics MathUs.ru Calculation of resistances Problem 1. (MOSH, 2014, 9 10) There are 10 resistors with a resistance of 1 kΩ. Draw a diagram of an electrical circuit, the resistance of which is as

State higher educational institution "DONETSK NATIONAL TECHNICAL UNIVERSITY" Department of Physics REPORT on laboratory work 49

Uncharged glass cubes 1 and 2 were brought close together and placed in the electric field of a positively charged ball, as shown in the upper part of the figure. Then the cubes were pushed apart and only then they removed the charged

Option I Test on the topic "Direct electric current". 1. For a current to appear in a conductor, it is necessary that ... A - a force acts on its free charges in a certain direction. B - on his free

Problem 1 Demonstration version of the qualifying stage Electronics Grade 9 How will the interaction force between two point charges change if the distance between them is doubled? 1 will decrease into 2

Nurusheva Marina Borisovna Senior Lecturer, Department of Physics 023 NRNU MEPhI Electric current Electric current is a directed (ordered) movement of charged particles. Conditions for the existence of an electric

Ministry of Education of the Republic of Belarus Educational institution "MOGILEV STATE FOOD UNIVERSITY" Department of Physics STUDY OF THE LAWS OF DC. MEASURING RESISTANCE WITH A BRIDGE

Federal Agency for Education of the Russian Federation Ukhta State Technical University 4 Measurement of DC resistance Methodological instructions for laboratory work for students of all specialties

Ministry of Education of the Russian Federation GOU VPO USTU-UPI Department of Physics INDIVIDUAL HOME TASK IN PHYSICS TOPIC: DC LAWS METHODOLOGICAL INSTRUCTIONS AND TASKS

LABORATORY WORK 3 Study of electrical conductivity of metals Theoretical introduction Electrical conductivity of metals If a constant potential difference is maintained at the ends of a conductor, then inside the conductor

Option 1 1. Determine the current strength and voltage drop across the conductor R1 of the electrical circuit shown in Figure 121, if R1 = 2 Ohm, R2 = 4 Ohm, R3 = 6 Ohm, battery EMF Ε = 4 V, its internal resistance

The work of an electric current, power, Joule-Lenz's law 1. What is the time of passage of a current of 5 A through a conductor, if at a voltage at its ends of 120 V an amount of heat is released in the conductor,

Explanation of the phenomena 1. In fig. 1 shows a diagram of the installation, with the help of which the dependence of the voltage on the rheostat on the value of the flowing current was investigated when the rheostat slider moves from right to left.

Amperage and charge. Amperage in a bulb from a flashlight I = 0.3 A. How many electrons N pass through the cross-section of the filament during time t = 0, s? .3. What charge q will pass through the conductor with resistance

Laboratory work Measuring the resistance of conductors with a Wheatstone bridge Equipment: reochord, a set of unknown resistances, a galvanometer, a direct current source, two keys, a resistance box.

Laboratory work 3.3 RESEARCH OF DEPENDENCE OF POWER AND EFFICIENCY OF DC SOURCE ON EXTERNAL LOAD 3.3 .. Purpose of work

Physics. 8th grade. Demonstration option 2 (90 minutes) 1 Diagnostic thematic work 2 to prepare for the OGE in PHYSICS on the topic "Direct current" Instructions for performing the work To perform diagnostic

MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION Federal State Budgetary Educational Institution of Higher Professional Education "TYUMEN STATE ARCHITECTURAL AND CONSTRUCTION

Electrodynamics 1. When a resistor with unknown resistance is connected to a current source with an EMF of 10 V and an internal resistance of 1 Ohm, the voltage at the output of the current source is 8 V. What is the current strength

Solving problems on the topic "Electrodynamics" VT Zakharova, physics teacher at MAOU SOSH 37 Task 14. Five identical resistors with a resistance of 1 Ohm are connected to an electrical circuit through which current I flows

Purpose of work: to get acquainted with one of the methods for measuring the electrical resistance of resistors. Check the rules for adding resistances for different ways of connecting resistors. Objective: to assemble the circuit

PREPARATION for the OGE PART 1 ELECTRICAL PHENOMENA 1.Two point charges will be attracted to each other if the charges 1 are the same in sign and any modulo 2 are the same in sign and are necessarily the same in

Municipal budgetary educational institution "Secondary school 4", Sergiev Posad Laboratory work "Measurement of EMF and internal resistance of a current source" 10 "A" class

Physics test Laws of electric current Grade 8 1 option 1. In what units is the current measured? 1) In coulombs (Cl) 2) In amperes (A) 3) In ohms (Ohm) 4) In volts (V) 2. It is known that through the transverse

Topic 12. Constant electric current 1. Electric current and current strength The free charge carriers (electrons and / or ions) available in the substance in the normal state move chaotically. If you create an external

When completing tasks 1 7 in the answer field, write down one number that corresponds to the number of the correct answer. 1 The figure shows two identical electrometers, the balls of which have charges of opposite

65 7. DIRECT ELECTRIC CURRENT 7. Electric current, strength and current density Electric current is called the ordered (directed) movement of electric charges. Physical scalar current

FEDERAL AGENCY FOR EDUCATION STATE EDUCATIONAL INSTITUTION OF HIGHER EDUCATION "SAMARA STATE TECHNICAL UNIVERSITY" Department "General physics and physics of oil and gas production"

Deferred tasks (25) In the area of ​​space where there is a particle with a mass of 1 mg and a charge of 2 10 11 C, a uniform horizontal electric field is created. What is the strength of this field, if from

Laboratory work 1 Measuring the buoyancy force to learn how to measure the buoyancy force acting on bodies of different shapes immersed in water. Instruments and materials: bodies cylindrical, cubic and irregular

Goals: teaching: to systematize the knowledge and skills of students in solving problems and calculating equivalent resistances using models, frames, etc.

Developing: developing the skills of logical thinking, abstract thinking, the ability to replace equivalence schemes, to simplify the calculation of schemes.

Educational: fostering a sense of responsibility, independence, the need for skills acquired in the lesson in the future

Equipment: wire frame of a cube, tetrader, mesh of an endless chain of resistances.

DURING THE CLASSES

Updating:

1. Teacher: "Let's remember the series connection of resistances."

Students sketch a diagram on the blackboard.

and write

U about = U 1 + U 2

Y about = Y 1 = Y 2

Teacher: remember the parallel connection of resistances.

The student on the blackboard sketches an elementary diagram:

Y about = Y 1 = Y 2

; for for n equal

Teacher: And now we will solve the problems of calculating the equivalent resistance, the section of the circuit is presented in the form of a geometric figure or a metal mesh.

Problem number 1

The wire frame is in the form of a cube, the edges of which represent equal resistance R. Calculate the equivalent resistance between points A and B. To calculate the equivalent resistance of this frame, it is necessary to replace it with an equivalent circuit. Points 1, 2, 3 have the same potential, they can be connected into one node. And the points (vertices) of the cube 4, 5, 6 can be connected to another node for the same reason. Students have such a model on each desk. After completing the described actions, an equivalent circuit is drawn.

Equivalent resistance in the AC section; on CD; on DB; and finally for the series connection of resistances we have:

By the same principle, the potentials of points A and 6 are equal, B and 3 are equal. Students match these points on their model and get an equivalent circuit:

The calculation of the equivalent resistance of such a circuit is simple.

Problem number 3

The same model of a cube, with the inclusion in the chain between points 2 and B. Students connect points with equal potentials 1 and 3; 6 and 4. Then the diagram will look like this:

Points 1,3 and 6,4 have equal potentials, and the resistance current between these points will not flow and the circuit is simplified to the form; whose equivalent resistance is calculated as follows:

Problem number 4

Equilateral triangular pyramid, the edge of which has resistance R. Calculate the equivalent resistance when connected to the circuit.

Points 3 and 4 have equal potential, so no current will flow along edge 3,4. Students take it away.

Then the diagram will look like this:

Equivalent resistance is calculated as follows:

Problem number 5

Wire mesh with link resistance R. Calculate the equivalent resistance between points 1 and 2.

At point 0, the links can be separated, then the diagram will look like:

- resistance of one half symmetrical in 1-2 points. Parallel to it there is the same branch, therefore

Problem number 6

The star consists of 5 equilateral triangles, the resistance of each .

Between points 1 and 2, one triangle is parallel to four, connected in series

Having experience in calculating the equivalent resistance of wire frames, you can begin to calculate the resistances of a circuit containing an infinite number of resistances. For example:

If you separate the link

from the general scheme, then the scheme will not change, then it can be presented in the form

or ,

we solve this equation with respect to R eq.

Lesson summary: we learned how to abstractly represent circuits of circuit sections, replace them with equivalent circuits, which make it easy to calculate the equivalent resistance.

Note: Present this model as: