The manual presents 20 options for test papers in physics for 7th grade students. Each test work contains 10 tasks that cover all the main topics of the physics course in the 7th grade of educational organizations. All tasks are given answers and a detailed system for evaluating their performance. The workshop is necessary for students of the 7th grade, teachers and methodologists who use standard tasks to prepare for the All-Russian test work.
The test work includes 10 tasks, the completion of which takes 1 lesson (45 minutes). 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 the correct one next to it.
When performing work, it is allowed to use a calculator.
VLOOKUP. Physics. 7th grade. Workshop. Ivanova V.V.
Description of the tutorial
OPTION 1
Fill in the right column of the table by entering the words water, time, difu
zia, a stone according to the words in the left column.
Answer:
Value of division_
Instrument reading_
The vehicle speed is 60 km/h. How far will he travel in 10 minutes? Write down the formula and do the calculations.
Answer:
The capacity of the gas tank of the motorcycle is 16 liters, the density of gasoline is 710 kg/m3. Find the mass of gasoline filling the gas tank. Write down the formula and do the calculations. 1 l = 0.001 m3.
Answer:
NAME OF FORCE A) Elastic force B) Friction force
DEFINITION
1) The force with which the Earth attracts bodies to itself
2) Occurs when one body moves on the surface of another
3) Acts on the support or stretches the suspension
4) Occurs when the body is deformed. Write down the selected numbers in the table under the corresponding letters.
Answer:
1) Pressure is measured in pascals.
2) Atmospheric pressure is measured with a dynamometer.
3) The pressure of the liquid on the bottom and walls of the vessel is inversely proportional to the density of the liquid and the height of the liquid column.
4) A hydraulic press is a machine that gives a gain in strength.
5) In communicating vessels, the liquid level is always the same.
Answer:
The Archimedean force acting on a body immersed in a liquid turned out to be less than the force of gravity. What will happen to the body?
Answer:_
The picture shows a falling ball. Draw the force of gravity acting on the ball in this figure.
The load is kept in balance with the help of the block shown in the figure, acting by the force F = 8 N. What is the weight of the load?
Answer:
An athlete throws a ball with a mass of 0.45 kg (see figure). What is the kinetic energy of the ball? 10 m/s
Answer:
OPTION 2
Fill in the right column of the table by entering the words and phrases power, glass, parachutist's descent, cabinet in accordance with the words in the left column.
Physical body
Substance
Physical quantity
physical phenomenon
Look carefully at the drawing. Write down the scale division and the meter reading.
Answer:
Value of division_
Instrument reading_
At what speed was the motorcycle moving if it traveled 15 kilometers in 20 minutes? Express your answer in km/h. Write down the formula and do the calculations.
Answer:
You can pour 200 grams of water into a glass. Find the capacity of this glass if the density of water is 1 g/cm3. Write down the formula and do the calculations.
Answer:
Establish a correspondence between the name of the force and its definition.
POWER NAME DEFINITION
A) Body weight 1) Occurs when one body moves along
B) The gravity of the surface of another
3) Occurs when the body is deformed
4) The force with which the Earth attracts bodies to itself
Write in the table the selected numbers under the corresponding letters.
Answer:
Select two correct statements from the proposed list and write down the numbers under which they are indicated.
The pressure of a solid body is a physical quantity equal to the ratio of the force acting perpendicular to the surface to the area of this surface.
The pressure of a liquid on the bottom and walls of a vessel is directly proportional to the density of the liquid and inversely proportional to the height of the liquid column.
Gateways are an example of communicating vessels. Atmospheric pressure increases with altitude.
A hydraulic press is a rigid body that can rotate around a fulcrum.
Answer:
The balloon was filled with helium. The Archimedean force acting on the ball turned out to be greater than the force of gravity. What will happen to the ball?
Answer:
The figure shows a bar sliding on the surface of the table. Draw the force of gravity acting on the block in this figure.
The figure shows a lever. Force Fx \u003d 20 N, force F2 \u003d 40 forces 1g \u003d 4 dm. Find the length of the arm of the force 12. The weight of the press arm is small. Write down the formula and do the calculations.
Answer:
An apple weighing 150 g is hanging on an apple tree branch (see figure). What is the potential energy of the apple?
Write formulas and do calculations. Express your answer in joules.
Answer:
X
OPTION 3
Fill in the right column of the table by entering the words and phrases air, skateboard movement, volume, bar in accordance with the words in the left column.
Physical body
Substance
Physical quantity
physical phenomenon
Look carefully at the drawing. Write down the scale division and the meter reading.
Answer:
Value of division_
Instrument reading_
The speed of the bus is 50 km/h. How far will he travel in 90 minutes? Write down the formula and do the calculations.
Answer:
The silver ring has a mass of 5.25 g and a volume of 0.5 cm3. Find the density of silver in g/cm3. Write down the formula and do the calculations.
Answer:
1 5 1 Match the name of the force with its definition.
NAME FORCE A) Force of elasticity B) Force of gravity
DEFINITION
1) Occurs when the body is deformed
2) Acts on the support or stretches the suspension
3) The force with which the Earth attracts bodies to itself
4) Occurs when one body moves on the surface of another
Write in the table the selected numbers under the corresponding letters. Answer:
Select two correct statements from the proposed list and write down the numbers under which they are indicated.
1) The pressure exerted on a wooden block by a weight placed on top is transmitted in all directions without change.
2) Atmospheric pressure is measured with a beaker.
3) In communicating vessels, the height of a liquid column with a higher density will be less than the height of a liquid column with a lower density.
4) According to Pascal's law, the pressure exerted on a liquid or gas is transmitted with increasing pressure to each point of the liquid or gas.
5) The action of the hydraulic press is based on Pascal's law.
Answer:
A toy boat floats in the pool. A small weight was placed on it. What will happen to the ship?
VLOOKUP. Physics. 7th grade. Workshop.
The All-Russian verification work of the VPR in physics was written on April 10, 2018 by students of 11 classes of Russian schools.
This test is not mandatory and is carried out in 2018 by the decision of the school. The test work is intended for graduates who have not chosen physics for passing the exam.
At the end of December 2017, demonstration versions of the VPR for grades 11 of 2018 were published on the official website of the FIPI.
After conducting work on the network, real options with answers appeared.
VPR options in physics Grade 11 with answers 2018
| Option 1 | answers + evaluation criteria |
| Option 2 | answers + evaluation criteria |
| Option 3 | |
| Option 4 | |
| Option 5 | answers + evaluation criteria |
| Option 6 | answers + evaluation criteria |
| Option 9 | answers + evaluation criteria |
| Option 10 | answers + evaluation criteria |
| Option 11 | |
| Option 12 |
The physics test includes 18 tasks, 1 hour 30 minutes (90 minutes) is allotted for its completion. VPR participants in physics are allowed to use a calculator.
The work checks the assimilation of all sections of the basic level physics course: mechanics, molecular physics, electrodynamics, quantum physics and elements of astrophysics.
Completing the tasks of the VPR in physics, eleventh-graders must demonstrate an understanding of the basic concepts, phenomena, quantities and laws studied in the course of physics, the ability to apply the knowledge gained to describe the structure and principles of operation of various technical objects or to recognize the studied phenomena and processes in the surrounding world. Also, within the framework of the VLOOKUP, the ability to work with textual information of physical content is checked.
Recommended scale for translating the total score for the performance of the VPR in physics into a mark on a five-point scale
All-Russian test works (VPR) are final tests organized in individual academic subjects to assess the level of preparation of schoolchildren, taking into account the requirements of federal state educational standards. Their organization provides for a unified schedule, the use of unified texts of tasks and unified assessment criteria.
VPR is not an analogue of the state final certification. They are held at the regional or school level.
The results can be used to form programs for the development of education at the level of municipalities, regions and the country as a whole, to improve the methods of teaching subjects in specific schools, as well as for individual work with students. The results of the VPR do not affect the receipt of a certificate and transfer to the next class. Rosobrnadzor does not recommend educational organizations to use the results of the VPR for setting annual grades for students.
In 2017, the All-Russian testing work of the VPR was tested in 11 classes in physics.
VPR is the usual control work in various subjects, but carried out on the same assignments and evaluated according to the same 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 largest number points.
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 \u003d 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. Bar temperatures in this 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 picture) is inserted into a hermetically sealed juice bag, inside of 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 a socket.
Write formulas and do calculations.
The formula for calculating the power of electric current is used:
9. Arrange the types of 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 of the 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
select the appropriate name of the physical phenomenon from the second column.
Write in the table the selected numbers under the corresponding letters.
| A | 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 of a 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 the 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 in the atmosphere, a solid body heats up due to deceleration, and an extensive luminous shell is formed around it, 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?
1. Task 17 No.
solar system
2. Task 1 No.
Concept group name
List of concepts
3. Task 18 No.
4. Task 2 No.
Selecttwo
5. Task 4 No.
1) decreases
2) increases
3) does not change
m
6. Task 5 No.
7. Task 5 No.
1) gas temperature;
3) the mass of a gas particle;
4) gas pressure;
5) momentum of a gas particle;
6) gas temperature.
8. Task 7 No.
Electrometer reading B
9. Task 9 No.
1) B
2) C
3) D
10. Task 6 No.
11. Task 10 No.
12. Task 12 No.
- multimeter;
- ruler;
In response:
13. Task 13 No.
EXAMPLESPHYSICAL PHENOMENA
A) lightning
A14. Task 14 No.
15. Task 15 No.
16. Task 16 No.
Read the text and complete tasks 16-18.
Answers
1. Task 17 No.
Determine the length of a year on Mars. Express your answer in days and round to the nearest whole number, counting a non-leap year on Earth.
Read the text and complete 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 the solar system and revolving around the sun. The table shows the main characteristics of the planets of the solar system.
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 the 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 in the atmosphere, a solid body heats up due to deceleration, and an extensive luminous shell is formed around it, consisting of hot gases. From strong air resistance, the meteoroid often breaks up, and its fragments - meteorites fall to the Earth with a roar.
Explanation.
From the table we find that the duration of the year on Mars is 1.88 of the duration of the year on Earth: 1.88 365 days ≈ 686 days.
Answer:686 days.
2. Task 1 No.
Read the list of concepts that you encountered in the course of physics:
charge, support reaction force, friction, electrometer, acceleration, electrical capacity.
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 nameList of concepts
Explanation.
Possible answer:
Concepts from dynamics - support reaction force, friction, acceleration.
Concepts from electrostatics - charge, electrometer, electric capacitance.
3. Task 18 No.
Is it possible to observe such a phenomenon as a fireball while on the moon? Explain the answer.
Explanation.
Possible answer:
1. You can't.
2. The moon has no atmosphere of its own. Space bodies falling to the surface of the Moon will not heat up (and glow) during the fall due to the lack of resistance forces.
4. Task 2 No.
The car is moving along a straight street. The graph shows the dependence of its speed on time.
Selecttwo statements that correctly describe the movement of the car, and write down the numbers under which they are indicated.
1) The first 3 s the car is stationary, and then it moves with uniform acceleration.
2) The first 3 s the car moves uniformly, and then uniformly accelerated.
3) The maximum vehicle speed for the entire observation period is 54 km/h.
4) After 10 seconds, the car stopped.
5) After 5 seconds, the car drove in the other direction.
Explanation.
1) The first 3 s the car moves uniformly, and then moves uniformly accelerated. The statement is not correct.
2) The first 3 s the car moves uniformly, and then uniformly accelerated. The statement is correct.
3) The maximum speed of the car is observed at the moment c and is: km / h. The statement is correct.
4) After 10 seconds, the car is moving uniformly. The statement is not correct.
5) After 5 s, the car moves uniformly slow, its speed module decreases linearly, and the direction of the speed vector was opposite to the direction of the acceleration vector. The statement is not correct.
Answer: 23.
5. Task 4 No.
Read the text and fill in the missing words. Words in the answer may be repeated.
1) decreases
2) increases
3) does not change
From the top of an inclined plane from a state of rest, a load of massm . When descending, the kinetic energy of the load is __________, the potential energy of the load is __________, the total mechanical energy of the load is __________.
Explanation.
As the height of a body above ground level decreases, its potential energy decreases. In this case, according to the law of conservation of energy, the total energy of the system remains unchanged, and the kinetic energy must increase.
Answer: 213.
6. Task 5 No.
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 90 °C, 80 °C, 50 °C, 30 °C. Which of the bars has a temperature of 80 °C?
Explanation.
Heat transfer occurs from a hotter body to a colder one. The direction of the arrows shows thatt a >t c , t a >t b , t b >t c , t b >t d , t c>t dor by combiningt a >t b >t c >t d .
So body B has a temperature of 80°C.
Answer:b.
7. Task 5 No.
An ideal gas in molecular physics is a theoretical gas model in which the size of gas particles can be neglected, the average kinetic energy of gas particles is many times greater than the potential energy of their interaction, collisions of gas particles with each other and with the walls of the vessel are absolutely elastic. An ideal gas can be described using macro and micro parameters. Choose from the proposed list three physical quantities that can be attributed to microparameters:
1) gas temperature;
2) average kinetic energy of gas particles;
3) the mass of a gas particle;
4) gas pressure;
5) momentum of a gas particle;
6) gas temperature.
Write the numbers in your answer in ascending order.
Explanation.
The microparameters of an ideal gas include characteristics related to individual molecules. From the proposed list, the microparameters are the average kinetic energy of gas particles, the mass of gas particles and the momentum of gas particles.
Answer: 235.
8. Task 7 No.
The figure shows two identical electrometers. Electrometer ball A is positively charged and shows 1 unit of charge, and electrometer ball B is not charged. What will be the readings of electrometers if their balls are connected with a thin ebonite rod?
Electrometer reading B
Explanation.
When connecting the balls with a thin ebonite stick, the redistribution of charges between the balls will not occur, since ebonite is not a conductor. This means that the readings of the electrometers will remain unchanged: electrometer A will show 1 unit, electrometer B - 0 units.
Answer: 1;0.
9. Task 9 No.
In the transformer shown in the figure, an alternating voltage is applied to input A. On windings B, C and D, an EMF of induction occurs. The number of turns is equal to that shown in the figure. Arrange windings B, C and D in order of increasing EMF of induction. Write down the corresponding sequence of numbers in your answer.
1) B
2) C
3) D
Explanation.
For transformer windings, the following relation for voltage (EMF) is valid:
This can be rewritten as:
Where 1 and 2 - corresponds to the first and second winding,U - winding voltage,n - the number of turns of the corresponding winding. Let's write the ratio of turns on different circuits to circuit A (according to the formula, A will always be the first circuit for us, and all the rest - the second):
The greater the ratio of turns, the greater the EMF of induction that occurs in the circuit.
Then, according to the increase in EMF, the circuits will be located in this way: C, D, B.
Answer: 231.
10. Task 6 No.
What happens to the nucleus during alpha decay?
1) The charge of the nucleus increases by one
2) The charge of the core is reduced by 2 units
3) The mass number is reduced by 2 units
4) Mass number increases by 2 units
Explanation.
During α-decay, the charge of the nucleus decreases by 2 units. The second statement is correct.
Answer: 2.
11. Task 10 No.
Speed is measured using a speedometer. The error in measuring speed with this speedometer is equal to its division value.
Record the speedometer reading in miles per hour (mph) in response, taking into account the measurement error, separated by a semicolon. For example, if the speedometer reads (51 ± 3) mph, then the answer should be "51; 3".
Explanation.
It can be seen from the figure that 2 divisions fit between the marks "40" and "60", which means that the division price is 10 mph. According to the condition, the measurement error is equal to the division price. The needle is at 50 mph. So the speedometer reads: (50 ± 10) mph.
Answer: 50;10.
12. Task 12 No.
You need to investigate how the capacitance of the capacitor depends on the area of the plates. The following equipment is available:
- multimeter;
- a set of four capacitors with different plates, but the same distance between them;
- ruler;
- constant voltage source.
Describe the procedure for conducting the study.
In response:
1. Draw or describe the experimental setup.
2. Describe the procedure for conducting research.
Explanation.
Possible answer:
1. We measure the source voltage with a multimeter.
2. We take the first capacitor, measure the area of its plates with a ruler.
3. We connect the capacitor to the source.
4. We measure the capacitance of the capacitor with a multimeter.
5. We take the next capacitor, we carry out the same measurements of area and capacitance.
6. The obtained capacitance values are compared.
13. Task 13 No.
Establish a correspondence between the examples and the physical phenomena that these examples illustrate. For each example of the manifestation of physical phenomena from the first column, select the appropriate name of the physical phenomenon from the second column.
EXAMPLESPHYSICAL PHENOMENA
A) lightning
b) the light from the light bulb illuminates the room
1) magnetic properties of metals
2) propagation of light in the atmosphere
3) accumulation of electric charge in the atmosphere
4) transition from liquid to gaseous state
Write in the table the selected numbers under the corresponding letters.
AExplanation.
Lightning is a giant electrical discharge in the atmosphere. (A - 3)
Light from a light bulb illuminates a room due to the properties of light to propagate through the atmosphere. (B - 2)
Answer: 32.
14. Task 14 No.
What physical phenomenon is caused by the operation of an internal combustion engine?
Read the text and do tasks 14 and 15.
Internal combustion engine
The main feature of any internal combustion engine is that the fuel ignites directly inside its working chamber, and not in additional external carriers. During operation, chemical and thermal energy from fuel combustion is converted into mechanical work. The principle of operation of the internal combustion engine is based on the physical effect of thermal expansion of gases, which is formed during the combustion of the fuel-air mixture under pressure inside the engine cylinders.
When the engine is started, an air-fuel mixture is injected into its cylinders through the intake valves and ignites there from a spark plug spark. During combustion and thermal expansion of gases from excess pressure, the piston sets in motion, transferring mechanical work to the rotation of the crankshaft. The operation of a piston internal combustion engine is carried out cyclically. These cycles are repeated at a frequency of several hundred times per minute. This ensures continuous translational rotation of the crankshaft exiting the engine.
A stroke is a work process that occurs in an engine in one stroke of the piston, more precisely, in one of its movements in one direction, up or down. A cycle is a set of measures that repeat in a certain sequence. According to the number of strokes within one working cycle, internal combustion engines are divided into two-stroke (the cycle is carried out in one revolution of the crankshaft and two strokes of the piston) and four-stroke (for two revolutions of the crankshaft and four pistons). At the same time, both in those and in other engines, the working process goes according to the following plan: intake; compression; combustion; expansion and release.
In a two-stroke internal combustion engine, the work of the piston is limited to two cycles, it makes a much smaller number of movements per unit of time than in a four-stroke engine. Friction losses are minimized. However, a lot of heat energy is released, and two-stroke engines heat up faster and more strongly. In two-stroke engines, the piston replaces the gas distribution valve mechanism, during its movement at certain moments, opening and closing the intake and exhaust working openings in the cylinder. Worse, compared with a four-stroke engine, gas exchange is the main drawback of a two-stroke ICE system. At the moment of removal of exhaust gases, a certain percentage of not only the working substance, but also power is lost. The areas of practical application of two-stroke internal combustion engines are mopeds and scooters; outboard motors, lawn mowers, chainsaws, etc. low-power equipment.
Explanation.
Possible answer: expansion of gases when heated.
15. Task 15 No.
Select two correct statements from the proposed list and write down the numbers under which they are indicated.
1) The main feature of any internal combustion engine is that the fuel ignites in additional external carriers.
2) The engine consists of cylinders.
3) In two-stroke internal combustion engines, the piston operation is limited to two cycles.
4) A beat is a set of beats that repeat in a certain sequence.
Explanation.
The main feature of any internal combustion engine is that the fuel ignites directly inside its working chamber, and not in additional external carriers. The first statement is not true.
The engine is made up of cylinders. The second statement is correct.
In a two-stroke internal combustion engine, the work of the piston is limited to two cycles. The third statement is correct.
A cycle is a set of measures that repeat in a certain sequence. The fourth statement is not true.
Answer: 23.
16. Task 16 No.
What do the two graphs show, which confirms Andrey's conclusion?
Read the text and complete tasks 16-18.
GREENHOUSE EFFECT: REALITY OR MYTH?
Living organisms need energy to live. The energy that sustains life on Earth comes from the Sun, which radiates energy into space. A tiny part of this energy reaches the Earth.
The Earth's atmosphere acts as a protective blanket that covers the planet's surface and protects it from the temperature fluctuations that would exist in an airless space.
Most of the energy emitted by the sun passes through the earth's atmosphere. The earth absorbs some of this energy, and the other part is reflected back from the earth's surface. Some of this reflected energy is absorbed by the atmosphere.
As a result, the average temperature above the earth's surface is higher than it would be if the atmosphere did not exist. The Earth's atmosphere acts like a greenhouse, hence the term "greenhouse effect".
It is believed that the greenhouse effect has become more pronounced during the twentieth century.
It is a fact that the average temperature of the Earth's atmosphere has increased. In newspapers and other periodicals, the main reason for rising temperatures in the twentieth century is often the increase in carbon dioxide emissions into the atmosphere.
A schoolboy named Andrei became interested in a possible connection between the average temperature of the Earth's atmosphere and carbon dioxide emissions into the Earth's atmosphere.
In the library, he found the following two charts.
Based on these two graphs, Andrei concluded that the increase in the average temperature of the Earth's atmosphere is indeed due to an increase in carbon dioxide emissions.