This manual is fully consistent with the federal state educational standard(second generation).
The proposed manual is intended to test the knowledge of 8th grade students. The publication provides an opportunity to form the skills and abilities necessary for the successful implementation of the All-Russian verification work.
The publication contains 18 variants of verification papers.
All questions are answered.
Each verification work includes 12 tasks on the topics "Thermal phenomena", " electrical phenomena”, “Electromagnetic phenomena”, “Light phenomena” and covers all sections of physics studied in the 8th grade. The four tasks involve short form answer, in four tasks it is necessary to make a multiple choice, in one task it is necessary to insert missing words into the text and in three tasks a detailed answer is required.

Examples.
The figure shows a horseshoe-shaped permanent magnet. How they are directed (up, down, right, left, away from the observer, towards the observer) magnetic lines magnetic field at point A?

The air temperature was measured with a thermometer shown in the figure. The temperature measurement error is equal to the division value of the thermometer. Write down in your answer the result of temperature measurement, taking into account the error.

The glass rod was rubbed on silk. After that, finely cut pieces of paper began to stick to the stick. Select all the statements that correctly characterize these processes, and write down the numbers of the selected statements.
1) Wand and silk have charges of the same sign.
2) Wand and silk have charges of different signs.
3) Pieces of paper are not electrified.
4) There are positive and negative charges in pieces of paper.
5) The glass rod acquires a positive charge due to the excess of electrons.
6) The glass rod acquires a positive charge due to the lack of electrons.

Free download e-book in a convenient format, watch and read:
Download the book VPR, Physics, Grade 8, Practicum, Boboshina S.B., 2018 - fileskachat.com, fast and free download.

• Description of control measuring materials for conducting a test in PHYSICS in 2020, grade 8
• Physics, Grade 8, Control measuring materials, Boboshina S.B., 2014
• Notebook for laboratory work in physics, grade 8, To the textbook by A.V. Peryshkin "Physics. Grade 8”, Minkova R.D., Ivanova V.V., Stepanov S.V., 2020

VPR All-Russian Testing Work - Physics Grade 11

Explanations to the sample of the All-Russian verification work

When familiarizing yourself with the sample test work, it should be borne in mind that the tasks included in the sample do not reflect all the skills and content issues that will be tested as part of the All-Russian test work. A complete list of content elements and skills that can be tested in the work is given in the codifier of content elements and requirements for the level of training of graduates for the development of the All-Russian test work in physics. The purpose of the test sample is to give an idea of ​​the structure of the All-Russian test
work, the number and form of tasks, their level of complexity.

Work instructions

The test work includes 18 tasks. To complete the work in physics, 1 hour 30 minutes (90 minutes) is allotted.
Prepare answers in the text of the work according to the instructions for the tasks. If you write down an incorrect answer, cross it out and write down a new one next to it.
When performing work, it is allowed to use a calculator.
When completing assignments, you can use a draft. Draft entries will not be reviewed or graded.
We advise you to complete the tasks in the order in which they are given. To save time, skip the task that you can't complete right away and move on to the next one. If after completing all the work you have time left, you can return to the missed tasks.
The points you get for completed tasks are summed up. Try to complete as many tasks as possible and score the most points.
We wish you success!

The following are reference data that you may need when doing your job.

Decimal Prefixes

Constants
free fall acceleration on Earth g = 10 m/s 2
gravitational constant G = 6.7 10 -11 N m 2 / kg 2
universal gas constant R = 8.31 J/(mol K)
speed of light in vacuum c = 3 10 8 m/s
coefficient of proportionality in the Coulomb law k \u003d 9 10 9 N m 2 / C 2
electron charge modulus
(elementary electric charge) e = 1.6 10 –19 C
Planck's constant h = 6.6 10 –34 J s

1. Read the list of concepts that you encountered in the course of physics.

volume, diffusion, current strength, magnetic induction, boiling, light refraction

Divide these concepts into two groups according to your chosen attribute. Record in a table
the name of each group and the concepts included in this group.

2. The car is moving along a straight street. The graph shows the dependence of its speed on time.

Select two statements that correctly describe the movement of the car, and write down the numbers under which they are indicated.

1) The first 10 seconds the car moves evenly, and the next 10 seconds it stands still.
2) The first 10 s the car moves uniformly accelerated, and the next 10 s - evenly.
3) The maximum vehicle speed for the entire observation period is 72 km/h.
4) After 30 seconds, the car stopped and then drove in the other direction.
5) The maximum vehicle acceleration module for the entire observation period is 3 m/s2.

25 (Numbers may be given in any order.)

3. A person is trying to move the piano along the wall. Draw the force in this picture.
that act on the piano, and the direction of its acceleration, if the instrument succeeded
move from place.

Four forces are correctly depicted: gravity, support reaction force, traction force and friction force. (The Archimedes force acting from the air is not taken into account).

Wherein:

• modules of vectors of gravity and force of support reaction approximately
  are the same in size;
• the modulus of the traction force is greater than the modulus of the friction force.

The correct direction of the acceleration vector is indicated (in the direction of the thrust force)

4. Read the text and fill in the missing words:

decreases
increases
does not change

Words in the answer may be repeated.

An icicle came off the roof of the house. As it falls, the kinetic energy of the icicle is _____________________, its potential energy relative to the surface of the Earth is ____________________. If we neglect the air resistance, then we can say that the total mechanical energy of the icicle is ______________________.

The words are inserted in the following order:
increases
decreases
does not change

5. Four metal bars (A, B, C and D) are placed close to each other, as shown in the figure. The arrows indicate the direction of heat transfer from bar to bar. The temperatures of the bars at the moment are 100 °C, 80 °C, 60 °C, 40 °C. Which of the bars has a temperature of 60 °C?

Answer: bar

6. A curved cocktail tube (see figure) is inserted into a hermetically sealed juice bag, inside which there is a small column of juice. If you wrap your hands around the bag and heat it without exerting pressure on it, the column of juice begins to move to the right towards the open end of the tube. Select all the statements that correctly characterize the process that occurs with the air in the bag, and write down the numbers of the selected statements.

1) The air in the bag expands.
2) The air in the bag is compressed.
3) The air temperature drops.
4) The air temperature rises.
5) The air pressure in the bag remains unchanged.
6) The air pressure in the bag rises.

145 (Numbers may be given in any order.)

7. The figure shows two identical electrometers, the balls of which have charges of opposite signs. What will be the readings of both electrometers if their balls are connected with a thin copper wire?

Answer:
Electrometer reading A: _____
Electrometer reading B: _____

Electrometer reading A: 0.5
Electrometer reading B: 0.5

8. In the passport of the electric hair dryer it is written that the power of its engine is 1.2 kW at a voltage of 220 V. Determine the strength of the current flowing through the electric circuit of the hair dryer when it is plugged into an outlet.

Write formulas and do calculations.

The formula is used to calculate the power electric current:

9. Arrange views electromagnetic waves emitted by the Sun, in ascending order of their
frequencies. Write down the corresponding sequence of numbers in your answer.

1) x-rays
2) infrared radiation
3) visible radiation

Answer: ____ → ____ → _____

10. The figure shows a fragment Periodic system chemical elements DI. Mendeleev. An isotope of uranium undergoes α-decay, in which a helium nucleus and the nucleus of another element are formed. Determine which element is formed during the α-decay of an isotope of uranium.

Answer: _____________________

11. Barometric pressure was measured using a barometer. The upper scale of the barometer is graduated in mm Hg. Art., and the lower scale is in kPa (see figure). The error in pressure measurement is equal to the scale division of the barometer.

Write down the barometer reading in mm Hg. Art. taking into account the measurement error.

Answer: ____________________________________

Any record of the answer is allowed, indicating the readings and taking into account the measurement error

A) (764 ± 1) mm Hg. Art.
B) from 763 to 765
B) 763< p < 765

12. You need to investigate how the period of oscillation of a spring pendulum depends on the mass of the load. The following equipment is available:

− electronic stopwatch;
− a set of three springs of different stiffness;
− a set of five weights of 100 g;
− tripod with clutch and foot.

Describe the procedure for conducting the study.

In response:
1. Draw or describe the experimental setup.
2. Describe the procedure for conducting research.

Answer: __________________________________________________________________________

________________________________________________________________________________

1. The setup shown in the picture is used: one of the springs, several weights and a stopwatch.
2. One load is suspended from the spring and the time of 10 oscillations is measured. The resulting time is divided by the number of oscillations, and the period is obtained.
3. Two weights are suspended from the spring, and the period measurements are repeated. Similar measurements can be made by adding more weights.
4. The obtained values ​​of the periods are compared

13. Establish a correspondence between examples and physical phenomena that these examples
illustrate. For each example of the manifestation of physical phenomena from the first column
choose the appropriate name physical phenomenon from the second column.

Write in the table the selected numbers under the corresponding letters.

BUT	B

Read the text and do tasks 14 and 15.

induction cookers

Under the glass-ceramic surface of the induction cooker is an inductor. An alternating electric current flows through it, creating an alternating magnetic field. Eddy or induction currents are induced in the bottom of the dishes, which heat the bottom, and from it the products placed in the dishes. The frequency of the alternating current in the inductor is 20-60 kHz, and the higher it is, the stronger the eddy currents in the bottom of the dish.

Unlike a conventional gas stove, there is no heat transfer from the bottom up, from the burner through the glass-ceramic surface to the dishes, which means there is no heat loss. In terms of energy efficiency, an induction cooker compares favorably with all other types of cookers: it heats up faster than on a gas or conventional electric cooker.

Induction cooker device:
1 - dishes with a bottom made of ferromagnetic material;
2 – glass-ceramic surface;
3 - insulation layer;
4 - inductor

Induction cookers require the use of metal utensils with
ferromagnetic properties (a magnet must be attracted to the dishes). And the thicker
bottom, the faster it heats up.

14. What physical phenomenon underlies the operation of an induction cooker?

The phenomenon of electromagnetic induction
(or electromagnetic induction)

15. Choose from the proposed list two true statements and write down the numbers under which they are indicated.

1) The action of the induction cooker is based on the action magnetic field on a conductor with current.
2) The heating of food in dishes on an induction cooker is associated with the thermal effect of an electric current.
3) The induction current that heats the dishes depends on the frequency of the alternating current in the inductor.
4) The bottom of cookware for induction cookers can be made of glass.
5) The heating efficiency of a conventional electric stove is higher than that of an induction one.

23 (Numbers may be given in any order.)

Read the text and do tasks 16-18.

solar system

The central object of the solar system is the star Sun. The vast majority of the entire mass of the system (about 99.866%) is concentrated in the Sun; it holds by its gravity the planets and other bodies belonging to solar system and revolving around the sun. The table shows the main characteristics of the planets of the solar system.

Table.
Comparative table of some parameters of the planets

*Parameters in the table are indicated in relation to similar Earth data.

Between the orbits of Mars and Jupiter is the main belt of asteroids - minor planets. There are many asteroids; they collide, break up, change each other's orbits, so that some fragments cross the Earth's orbit during their movement.

The passage of fragments (meteor bodies) through earth's atmosphere looks like "shooting stars" from the Earth's surface. On rare occasions when larger fragments pass, a fireball can be seen flying across the sky. This phenomenon is called a fireball.

Moving through the atmosphere solid heats up due to deceleration, and around it an extensive luminous shell is formed, consisting of hot gases. From strong air resistance, the meteoroid often breaks up, and its fragments - meteorites fall to the Earth with a roar.

16. Which of the parameters indicated in the table increases as the planet moves away fromsun?

- a control event carried out at the all-Russian level according to a single standard. When the new method of knowledge control was officially approved, the Ministry of Education explained its importance as follows: VPR will allow monitoring not only the level of knowledge, but also the effectiveness of the methodological apparatus used by teachers in a particular school in the Russian Federation.

However, these good intentions do not negate the fact that the introduction of VPR was an unpleasant surprise for graduates. Not only do they have a lot of the most difficult ones, but they also need to learn a few additional subjects, many of which will not even come in handy when. One of the most complex disciplines submitted for the all-Russian measurement of knowledge is physics - a science characterized by a voluminous categorical apparatus, numerous laws and difficult calculations.

Those who are already taking physics exams will definitely not have to worry about CDF. Well, for schoolchildren who do not plan to connect their lives with exact sciences, it will be useful to learn all the subtleties of grading and writing a VLOOKUP, including the structure and content of the work. Even though CDF does not affect your ability to get a high school diploma, you don't want to arouse the teacher's wrath by writing a test with an unsatisfactory result.

Demo version of VLOOKUP in physics

Date and regulations of VPR-2018 in physics

In the VPR schedule for 2017/2018 academic year for control work in physics allotted March 10, 2018. The VPR regulation in physics states that the student must cope with his option in 90 minutes. When solving the control work, students will be able to use a calculator for calculations, which does not have a programming function and the ability to store information. Primary score, scored by an eleventh grader for the VPR, is translated into grades as determined by the teachers' council of each particular school.

This work will make a final measurement of knowledge of 11th grade graduates. The basic level of training assumes that students can easily understand and explain physical terms and apply their knowledge in everyday life. Based on the results of the control work, the relevant department will conclude whether it is advisable to make changes to school curriculum and whether it is necessary to improve the professional skills of subject teachers.

As the main sections submitted for verification within the framework of the VPR, the relevant commission named mechanics, molecular and quantum physics, elements of astrophysics, as well as a section that studies electrodynamics. When evaluating control works, the commission will check:

• knowledge of the categorical apparatus of this science (i.e. phenomena, quantities and units of their measurement, the goals of physics and ways to achieve them through the use of various equipment);
• the ability to interpret the information received and data presented in graphical and tabular form;
• understanding how the laws of physics work;
• the ability to describe and characterize processes using physical quantities;
• willingness to apply the formulas used in physics;
• the ability to read the readings of instruments (beaker, dynamometer, barometer, voltmeter and ammeter), to conduct observations and experiments according to the proposed hypotheses;
• the ability to explain the physical phenomena that occur in the surrounding world.

At the VPR in physics, 18 tasks await you, for which 90 minutes are allotted

Structural features of CDF in physics

In each version of the test, students will be offered 18 tasks that differ in the form and complexity of the solution:

• tasks from 1 to 10 are basic, testing knowledge of terminology, basic quantities and the main laws of physics. Three of the tasks are in the mechanics section, two are in the molecular physics section, three are in electrodynamics, and one is in quantum physics;
• tasks 11 and 12 will test the methodological skills of schoolchildren. In the first one, you will need to write down the readings of the device, based on the proposed photo, and in the second, you will sketch out a plan for a simple experiment, adhering to a certain hypothesis;
• tasks 13-15 check how well eleventh graders can use physical knowledge when describing various devices and devices (including those that they use in everyday life), and whether they can characterize the principle of their work;
• tasks 16-18 will test the skills of working with physical texts and information in the form of a table, diagram or graph.

The 13 test tasks require that the student write a short answer in the form of a number, symbol, correct word or phrase, or simply select the correct answer from the list provided. For 5 tasks, you will need to give a detailed answer - these can be several sentences describing the stages of the experiment, or filling in the gaps in the table.

In total, it will be possible to score 26 points for the control work, 19 (or 73%) of which can be obtained for solving 14 simple tasks, and 7 points (27%) for working with 4 complex tasks.

How to prepare for the VPR in physics?

Spend time not only on textbooks, but also on working through the VLOOKUP demo

From the structure of the ticket, it is clear that it will definitely not work to score a high score by learning only physical terms and laws. If your goal is to earn maximum points, then you need to thoroughly understand the logic of calculations, remember and understand the formulas, and analyze the mechanism of action and manifestation of physical laws. Schoolchildren who wrote VPR in physics last year, as well as subject teachers, give the following preparation recommendations:

• be sure to download and solve the demo version of the VLOOKUP 2018, which was developed by specialists from FIPI (see links at the beginning of the article). So you will understand how the ticket is built and evaluate your level of preparation;
• if you didn’t choose, then to prepare for the VPR it will be enough to repeat the materials set out in school textbooks;
• students who are not strong in experiments and do not know how a particular device works should consult with a tutor or watch videos that clearly demonstrate how to work with various equipment and read readings;
• to consolidate the terminology, take several online tests.

In 2017, the All-Russian testing work of the VPR was tested in 11 classes in physics.

VPR are ordinary test papers on various subjects, but carried out according to uniform tasks and evaluated according to uniform criteria developed for the whole country.

To understand how to perform verification work, you should first of all familiarize yourself with the demo versions of the control measuring materials (CMM) of the VPR for the subjects of this year.

Official website of VPR (StatGrad)- vpr.statgrad.org

Demo version of VLOOKUP 11th grade in physics 2017

Demonstration options in physics for grade 11 will help to get an idea of ​​the structure of future KIM, the number of tasks, their form and level of complexity. In addition, the demo version provides criteria for evaluating the performance of tasks with a detailed answer, which give an idea of ​​the requirements for the completeness and correctness of the answer recording.

This information is useful, it can be used in drawing up a plan for repeating the material before the test work in physics.

Variants of VPR 2017 in physics Grade 11

Option 9	answers + criteria
Option 10	answers + criteria
Option 11	answers + evaluation criteria
Option 12	answers + evaluation criteria
Option 13	download
Option 14	download
Option 19	*
Option 20	*

* Options 19, 20 can be used for home preparation, since we have not yet been able to find answers on the Internet.

The test work includes 18 tasks. To complete the work in physics, 1 hour 30 minutes (90 minutes) is allotted.

Prepare answers in the text of the work according to the instructions for the tasks. If you write down an incorrect answer, cross it out and write down a new one next to it.

When performing work, it is allowed to use a calculator.

When completing assignments, you can use a draft. Draft entries will not be reviewed or graded.

We advise you to complete the tasks in the order in which they are given. To save time, skip the task that you can't complete right away and move on to the next one. If after completing all the work you have time left, you can return to the missed tasks.

The points you get for completed tasks are summed up. Try to complete as many tasks as possible and score the most points.

The authors: Lebedeva Alevtina Sergeevna, Teacher of physics, work experience 27 years. Diploma of the Ministry of Education of the Moscow Region (2013), Gratitude of the Head of the Voskresensky Municipal District (2015), Diploma of the President of the Association of Teachers of Mathematics and Physics of the Moscow Region (2015).

Preparation for the OGE and the Unified State Examination

Average general education

UMK line N. S. Purysheva. Physics (10-11) (BU)

Line UMK G. Ya. Myakishev, M.A. Petrova. Physics (10-11) (B)

Line UMK G. Ya. Myakishev. Physics (10-11) (U)

The All-Russian test work includes 18 tasks. To complete the work in physics, 1 hour 30 minutes (90 minutes) is allotted. When completing tasks, you are allowed to use a calculator. The work includes groups of tasks that test skills that are integral part requirements for the level of training of graduates. When developing the content of the test work, the need to assess the assimilation of content elements from all sections of the basic level physics course is taken into account: mechanics, molecular physics, electrodynamics, quantum physics and elements of astrophysics. The table shows the distribution of tasks by sections of the course. Some of the tasks in the work are complex in nature and include elements of content from different sections, tasks 15–18 are built on the basis of text information, which can also refer to several sections of the physics course at once. Table 1 shows the distribution of tasks for the main substantive sections of the physics course.

Table 1. Distribution of tasks according to the main substantive sections of the physics course

The VWP is developed based on the need to verify the requirements for the level of training of graduates. Table 2 shows the distribution of tasks by basic skills and methods of action.

Table 2. Distribution of tasks by types of skills and methods of action

Basic skills and methods of action	Number of tasks
Know/understand meaning physical concepts, quantities, laws. Describe and explain physical phenomena and properties of bodies
Explain the structure and principle of operation of technical objects, give examples of the practical use of physical knowledge
Distinguish between hypotheses scientific theories, draw conclusions based on experimental data, conduct experiments to study the studied phenomena and processes
Perceive and, on the basis of the acquired knowledge, independently evaluate the information contained in the media, the Internet, popular science articles

Evaluation system for individual tasks and work in general

Tasks 2, 4–7, 9–11, 13–17 are considered completed if the answer recorded by the student matches the correct answer. The performance of each of the tasks 4-7, 9-11, 14, 16 and 17 is estimated by 1 point. The performance of each of the tasks 2, 13 and 15 is evaluated by 2 points if both elements of the answer are correctly indicated; 1 point if an error was made in one of the given answers. The performance of each of the tasks with a detailed answer 1, 3, 8, 12 and 18 is evaluated taking into account the correctness and completeness of the answer. Instructions are provided for each task with a detailed answer, which indicates what each point is set for - from zero to the maximum score.

Exercise 1

Read the list of concepts that you met in the physics course: Convection, degrees Celsius, Ohm, Photoelectric effect, Light dispersion, centimeter

Divide these concepts into two groups according to your chosen attribute. Write in the table the name of each group and the concepts included in this group.

Concept group name	List of concepts

Solution

In the task, it is required to divide the concepts into two groups according to the selected attribute, write down the name of each group and the concepts included in this group in the table.

To be able to choose from the proposed phenomena only physical ones. Remember the list of physical quantities and their units of measurement.

The body moves along the axis OH. The figure shows a graph of the dependence of the projection of the body velocity on the axis OH from time t.

Using the picture, choose from the proposed list two

1. At the point in time t 1 body was at rest.
2. t 2 < t < t 3 the body moved uniformly
3. During the time interval t 3 < t < t 5 the coordinate of the body did not change.
4. At the point in time t t 2
5. At the point in time t 4 the modulus of acceleration of the body is less than at the moment of time t 1

Solution

Performing this task, it is important to correctly read the graph of the dependence of the projection of speed on time. Determine the nature of the movement of the body in certain areas. Determine where the body rested or moved uniformly. Select the area where the speed of the body changed. From the proposed statements, it is reasonable to exclude those that do not fit. As a result, we stop at the correct statements. it statement 1: At the point in time t 1 the body was at rest, so the velocity projection is 0. Statement 4: At the point in time t 5 body coordinate was greater than at time t 2 when v x= 0. The projection of the body velocity was larger in its value. Having written the equation for the dependence of the body coordinate on time, we see that x(t) = v x t + x 0 , x 0 is the initial coordinate of the body.

Difficult questions of the exam in physics: Methods for solving problems on mechanical and electromagnetic oscillations

The body floats up from the bottom of a glass of water (see figure). Draw in this figure the forces acting on the body and the direction of its acceleration.

Solution

Read the assignment carefully. Pay attention to what happens to the cork in the glass. Cork floats from the bottom of a glass of water, and with acceleration. Specify the forces acting on the cork. This is the force of gravity t acting from the Earth, the force of Archimedes a, acting from the side of the liquid, and the force of resistance of the liquid c. It is important to understand that the sum of the modules of the vectors of gravity and the drag force of the fluid is less than the module of the Archimedean force. This means that the resulting force is directed upwards, according to Newton's second law, the acceleration vector has the same direction. The acceleration vector is directed in the direction of the Archimedes force a

Task 4

Read the text and fill in the missing words: decreases; increases; does not change. Words in the text may be repeated.

The figure skater, standing on the ice, catches a bouquet that flew up to him horizontally. As a result, the speed of the bunch is _______________, the speed of the skater is ________________, the momentum of the body system of the skater is the bunch of ___________.

Solution

In the task, you need to remember the concept of body momentum and the law of conservation of momentum. Before the interaction, the skater's momentum was zero, so he rested relative to the Earth. The momentum of the bouquet is maximum. After the interaction, the skater and the bouquet begin to move together at a common speed. Therefore, the bouquet speed decreases, skater's speed increases. In general, the impulse of the skater-bouquet system is does not change.

Methodological assistance to a physics teacher

Four metal bars were placed close to each other, as shown in the figure. The arrows indicate the direction of heat transfer from bar to bar. The temperatures of the bars at the moment are 100 °C, 80 °C, 60 °C, 40 °C. A bar has a temperature of 60 ° C.

Solution

The change in internal energy and its transfer from one body to another occurs in the process of interaction of bodies. In our case, the change in internal energy occurs due to the collision of randomly moving molecules of contacting bodies. Heat transfer between the bars occurs from bodies with greater internal energy, to the bars with less internal energy. The process continues until they reach thermal equilibrium.

Bar B has a temperature of 60°C.

The figure shows PV-diagram of processes in an ideal gas. The mass of the gas is constant. Which area corresponds to Isochoric heating.

Solution

In order to correctly select the section of the graph corresponding to isochoric heating, it is necessary to recall isoprocesses. The task is simplified by the fact that the graphs are given in axes PV. Isochoric heating, a process in which the volume of an ideal gas does not change, but pressure increases with increasing temperature. Remember, this is Charles' law. Therefore, this area OA. We exclude the site OS, where the volume also does not change, but the pressure decreases, which corresponds to the cooling of the gas.

Metal ball 1, mounted on a long insulating handle and having a charge + q, are brought in turn into contact with two of the same balls 2 and 3, located on insulating supports and having, respectively, charges - q and + q.

What charge will remain on the ball number 3.

Solution

After the interaction of the first ball with the second ball of the same size, the charge of these balls will become equal to zero. Since modulo these charges are the same. After the contact of the first ball with the third one, the charge will be redistributed. The charge will be shared equally. Will by q/2 on each.

Answer: q/2.

Task 8

Determine how much heat will be released in the heating coil in 10 minutes, when an electric current of 2 A flows. The resistance of the coil is 15 Ohm.

Solution

First of all, let's convert the units of measurement to the SI system. Time t= 600 s, Further, we note that when the current passes I = 2 A in spiral with resistance R\u003d 15 Ohm, during 600 s the amount of heat is released Q = I 2 Rt(Joule-Lenz law). Substitute the numerical values ​​into the formula: Q= (2 A)2 15 Ohm 600 s = 36000 J

Answer: 36000 J.

Task 9

Arrange the types of electromagnetic waves emitted by the Sun in decreasing order of their wavelengths. X-ray, infrared, ultraviolet

Solution

Familiarity with the scale of electromagnetic waves suggests that the graduate must clearly understand in what sequence electromagnetic radiation is located. Know the relationship between wavelength and radiation frequency

where v is the radiation frequency, c is the propagation speed of electromagnetic radiation. Remember that the speed of propagation of electromagnetic waves in vacuum is the same and equal to 300,000 km/s. The scale begins with long waves of a lower frequency, this is infrared radiation, the next radiation with a higher frequency, respectively, is ultraviolet radiation and the higher frequency of the proposed ones is x-ray radiation. Realizing that the frequency increases and the wavelength decreases, we write in the desired sequence.

Answer: Infrared radiation, ultraviolet radiation, X-ray radiation.

Using a fragment of the Periodic Table of Chemical Elements shown in the figure, determine the isotope of which element is formed as a result of the electronic beta decay of bismuth

Solution

β - decay into atomic nucleus occurs as a result of the transformation of a neutron into a proton with the emission of an electron. As a result of this decay, the number of protons in the nucleus increases by one, and the electric charge increases by one, while the mass number of the nucleus remains unchanged. Thus, the transformation reaction of an element is as follows:

in general view. For our case we have:

The charge number 84 corresponds to polonium.

Answer: As a result of the electronic beta decay of bismuth, polonium is formed.

On improving the methods of teaching physics in Russia: from the 18th to the 21st century

Task 11

A) The division value and the measurement limit of the device are equal, respectively:

1. 50 A, 2A;
2. 2mA, 50mA;
3. 10 A, 50 A;
4. 50 mA, 10 mA.

B) Record the result electrical voltage, given that the measurement error is equal to half the division value.

1. (2.4 ± 0.1) V
2. (2.8 ± 0.1) V
3. (4.4 ± 0.2) V
4. (4.8 ± 0.2) V

Solution

The task tests the ability to record the readings of measuring instruments, taking into account the specified measurement error and the ability to correctly use any measuring instrument (beaker, thermometer, dynamometer, voltmeter, ammeter) in everyday life. In addition, it focuses on recording the result, taking into account significant figures. Determine the name of the device. This is a milliammeter. A device for measuring current strength. Units mA. The measurement limit is the maximum value of the scale, 50 mA. Division value 2 mA.

Answer: 2 mA, 50 mA.

If required, write down readings according to the drawing measuring instrument taking into account the error, then the execution algorithm is as follows:

We determine that the measuring device is a voltmeter. The voltmeter has two measurement scales. We pay attention to which pair of terminals is involved in the device, and therefore we work on the upper scale. Measurement limit - 6 V; Value of division With = 0.2 V; the measurement error according to the condition of the problem is equal to half the division value. ∆ U= 0.1 V.

Indications of the measuring device, taking into account the error: (4.8 ± 0.1) V.

• Paper;
• Laser pointer;
• Protractor;

In response:

1. Describe the procedure for conducting research.

Solution

You need to investigate how the angle of refraction of light changes depending on the substance in which the phenomenon of light refraction is observed. The following equipment is available (see picture):

• Paper;
• Laser pointer;
• Semicircular plates made of glass, polystyrene and rock crystal;
• Protractor;

In response:

1. Describe the experimental setup.
2. Describe the procedure

The experiment uses the setup shown in the figure. The angle of incidence and the angle of refraction are measured with a protractor. It is necessary to conduct two or three experiments in which the beam of a laser pointer is directed to plates of different materials: glass, polystyrene, rock crystal. The angle of incidence of the beam on the flat face of the plate is left unchanged, and the angle of refraction is measured. The obtained values ​​of the angles of refraction are compared.

VLOOKUP in questions and answers

Task 13

Establish a correspondence between examples of the manifestation of physical phenomena and physical phenomena. For each example from the first column, select the appropriate name of the physical phenomenon from the second column.

Write in the table the selected numbers under the corresponding letters.

Answer:

Solution

Let us establish a correspondence between examples of the manifestation of physical phenomena and physical phenomena. For each example from the first column, we select the corresponding names of the physical phenomenon from the second column.

Under the influence electric field of a charged ebonite rod, the needle of an uncharged electrometer deviates when the rod is brought near it. Due to the electrification of the conductor through influence. The magnetization of a substance in a magnetic field is manifested when iron filings are attracted to a piece of magnetic ore.

Answer:

Read the text and complete tasks 14 and 15

Electrostatic precipitators

On the industrial enterprises electrical purification of gases from solid impurities is widely used. The action of the electrostatic precipitator is based on the use of a corona discharge. You can do the following experiment: a vessel filled with smoke suddenly becomes transparent if sharp metal electrodes are introduced into it, oppositely charged from an electric machine.

The figure shows a diagram of the simplest electrostatic precipitator: two electrodes are contained inside a glass tube (a metal cylinder and a thin metal wire stretched along its axis). The electrodes are connected to electric car. If you blow a stream of smoke or dust through the tube and start the machine, then at some voltage sufficient to ignite the corona discharge, the outgoing stream of air becomes clean and transparent.

This is explained by the fact that when the corona discharge is ignited, the air inside the tube is strongly ionized. Gas ions stick to dust particles and thereby charge them. Charged particles under the influence of an electric field move to the electrodes and settle on them

Task 14

What process is observed in a gas in a strong electric field?

Solution

We carefully read the proposed text. We select the processes that are described in the condition. This is a corona discharge inside a glass tube. The air is ionized. Gas ions stick to dust particles and thereby charge them. Charged particles under the action of an electric field move to the electrodes and settle on them.

Answer: Corona discharge, ionization.

Task 15

Choose from the proposed list two true statements. List their numbers.

1. A spark discharge occurs between the two filter electrodes.
2. Silk thread can be used as a thin wire in the filter.
3. According to the electrode connection shown in the figure, negatively charged particles will settle on the walls of the cylinder.
4. At low voltages, air purification in the electrostatic precipitator will occur slowly.
5. A corona discharge can be observed at the tip of a conductor placed in a strong electric field.

Solution

To answer, we will use the text about electrostatic precipitators. We exclude incorrect statements from the proposed list using the description of electric air purification. We look at the figure and pay attention to the connection of the electrodes. The thread is connected to the negative pole, the cylinder wall to the positive pole of the source. Charged particles will settle on the walls of the cylinder. Correct statement 3. A corona discharge can be observed at the tip of a conductor placed in a strong electric field.

Read the text and complete Tasks 16-18

When exploring great depths, such underwater vehicles as bathyscaphes and bathyspheres are used. The bathysphere is a deep-sea submersible in the form of a ball, which is lowered into the water from the side of the ship on a steel cable.

Several prototypes of modern bathyspheres appeared in Europe in the 16th-19th centuries. One of them is a diving bell, the design of which was proposed in 1716 by the English astronomer Edmond Halley (see figure). The wooden bell, open at the base, accommodated up to five people, partially submerged in water. They received air from two casks lowered in turn from the surface, from where the air entered the bell through a leather sleeve. Wearing a leather helmet, the diver could also make observations outside the bell, receiving air from it through an additional hose. The exhaust air was released through a valve located at the top of the bell.

The main disadvantage of Halley's bell is that it cannot be used at great depths. As the bell sinks, the air density in it increases so much that it becomes impossible for them to breathe. Moreover, with a long stay of a diver in the zone high blood pressure there is saturation of the blood and tissues of the body with air gases, mainly nitrogen, which can lead to the so-called decompression sickness when a diver ascends from depth to the surface of the water.

Prevention of decompression sickness requires compliance with working hours and proper organization of decompression (exit from the high pressure zone).

The time spent by divers at depth is regulated by special diving safety rules (see table).

Task 16

How does the air pressure in the bell change as the bell sinks?

Task 17

How does the allowable diver work time change with increasing diving depth?

Task 16–17. Solution

We read the text carefully and examined the drawing of a diving bell, the design of which was proposed by the English astronomer E. Halley. We got acquainted with the table in which the time spent by divers at depth is regulated by special diving safety rules.

Pressure (in addition to atmospheric), atm.	Permissible time spent in the work area

The table shows that the greater the pressure (the greater the depth of immersion), the less time the diver can stay on it.

Task 16. Answer: Air pressure increases

Task 17. Answer: The allowable working time is decreasing

Task 18

Is it permissible for a diver to work at a depth of 30 m for 2.5 hours? Explain the answer.

Solution

The work of a diver at a depth of 30 meters for 2.5 hours is permissible. Since at a depth of 30 meters the hydrostatic pressure is approximately 3 × 10 5 Pa or 3 atm of the atmosphere) in addition to atmospheric pressure. The allowable time for a diver to stay at this pressure is 2 hours 48 minutes, which is more than the required 2.5 hours.