Ideal gas MKT type A Page 9 from 9
MCT IDEAL GAS
BASIC MKT EQUATION , ABSOLUTE TEMPERATURE
At a constant particle concentration, the absolute temperature of the ideal gas was increased by a factor of 4. The gas pressure in this case
increased 4 times
increased by 2 times
decreased by 4 times
hasn't changed
At a constant absolute temperature, the concentration of ideal gas molecules was increased 4 times. In this case, the gas pressure
increased 4 times
increased by 2 times
decreased by 4 times
hasn't changed
The vessel contains a mixture of gases - oxygen and nitrogen - with an equal concentration of molecules. Compare the pressure produced by oxygen ( R To) and nitrogen ( R A) on the walls of the vessel.
1) ratio R To And R A will be different at different temperatures of the gas mixture
2) R To = R A
3) R To > R A
4) R To R A
At a constant concentration of ideal gas particles, the average kinetic energy The thermal movement of its molecules decreased by 4 times. In this case, the gas pressure
decreased by 16 times
decreased by 2 times
decreased by 4 times
hasn't changed
As a result of cooling of a monatomic ideal gas, its pressure decreased by 4 times, but the concentration of gas molecules did not change. In this case, the average kinetic energy of thermal motion of gas molecules
decreased by 16 times
decreased by 2 times
decreased by 4 times
hasn't changed
At constant pressure, the concentration of gas molecules increased 5 times, but its mass did not change. Average kinetic energy forward motion gas molecules
The absolute body temperature is 300 K. On the Celsius scale it is equal to
1) – 27°С 2) 27°C 3) 300°С 4) 573°С
The temperature of the solid decreased by 17°C. On the absolute temperature scale, this change was
1) 290 K 2) 256 K 3) 17 K 4) 0 K
Measuring pressure p, temperature T and concentration of molecules n gas for which ideality conditions are satisfied, we can determine
gravitational constant G
Boltzmann constantk
Planck's constant h
Rydberg constant R
According to calculations, the temperature of the liquid should be 143 K. Meanwhile, the thermometer in the vessel shows a temperature of –130 °C. It means that
The thermometer is not designed for low temperatures and requires replacement
thermometer shows higher temperature
thermometer shows lower temperature
thermometer shows estimated temperature
At a temperature of 0 °C, the ice of the skating rink melts. Puddles form on the ice, and the air above it is saturated with water vapor. In which medium (ice, puddles or water vapor) is the average energy of movement of water molecules the highest?
1) in ice 2) in puddles 3) in water vapor 4) the same everywhere
When an ideal gas is heated, its absolute temperature doubles. How did the average kinetic energy of thermal motion of gas molecules change?
increased 16 times
increased 4 times
increased by 2 times
hasn't changed
Metal gas cylinders cannot be stored above a certain temperature, because otherwise they may explode. This is due to the fact that
The internal energy of a gas depends on temperature
gas pressure depends on temperature
gas volume depends on temperature
molecules break down into atoms and energy is released in the process
As the temperature of the gas in the sealed vessel decreases, the gas pressure decreases. This decrease in pressure is due to the fact that
the energy of thermal motion of gas molecules decreases
the energy of interaction of gas molecules with each other decreases
the randomness of the movement of gas molecules decreases
the size of gas molecules decreases as it cools
In a closed vessel, the absolute temperature of an ideal gas decreased by 3 times. In this case, the gas pressure on the walls of the vessel
The concentration of molecules of a monatomic ideal gas was reduced by 5 times. At the same time, the average energy of the chaotic movement of gas molecules was increased by 2 times. As a result, the gas pressure in the vessel
decreased by 5 times
increased by 2 times
decreased by 5/2 times
decreased by 5/4 times
As a result of heating the gas, the average kinetic energy of the thermal motion of its molecules increased 4 times. How did the absolute temperature of the gas change?
increased 4 times
increased by 2 times
decreased by 4 times
hasn't changed
CLIPERON-MENDELEEV EQUATION, GAS LAWS
The tank contains 20 kg of nitrogen at a temperature of 300 K and a pressure of 10 5 Pa. What is the volume of the tank?
1) 17.8 m 3 2) 1.8·10 -2 m 3 3) 35.6 m 3 4) 3.6·10 -2 m 3
A cylinder with a volume of 1.66 m 3 contains 2 kg of nitrogen at a pressure of 10 5 Pa. What is the temperature of this gas?
1) 280°С 2) 140°С 3) 7°C 4) – 3°С
At a temperature of 10 0 C and a pressure of 10 5 Pa, the gas density is 2.5 kg/m 3. What is the molar mass of the gas?
59 g/mol 2) 69 g/mol 3) 598 kg/mol 4) 5.8 10 -3 kg/mol
A vessel of constant volume contains an ideal gas in an amount of 2 mol. How should the absolute temperature of a container with a gas be changed when another mole of gas is added to the container so that the pressure of the gas on the walls of the container increases by 3 times?
reduce by 3 times
reduce by 2 times
increase 2 times
increase 3 times
A vessel of constant volume contains an ideal gas in an amount of 2 mol. How should the absolute temperature of a vessel with gas be changed when 1 mole of gas is released from the vessel so that the pressure of the gas on the walls of the vessel increases by 2 times?
increase 2 times
increase 4 times
reduce by 2 times
reduce by 4 times
A vessel of constant volume contains an ideal gas in an amount of 1 mole. How should the absolute temperature of a vessel with gas be changed so that when another 1 mole of gas is added to the vessel, the gas pressure on the walls of the vessel decreases by 2 times?
increase 2 times
reduce by 2 times
Single State exam in physics, 2003
demo version
Part A
A1. The figures show graphs of the dependence of the acceleration module on the time of movement. Which of the graphs corresponds to uniform rectilinear motion?
| 1) | 2) |
 |
|
| 3) |
 | 4) |
 |
Solution. In uniform linear motion, the acceleration is zero.
Correct answer: 2.
A2. The rocket engine of the first domestic experimental rocket using liquid fuel had a thrust force of 660 N. The launch weight of the rocket was 30 kg. What acceleration did the rocket acquire during launch?
| 1) | |
| 2) | |
| 3) | |
| 4) |
Solution. There are two forces acting on the rocket: gravity ( mg), downward, and traction force ( F), directed upward. According to Newton's second law:
Correct answer: 1.
A3. When the distance between the centers of spherical bodies increases by 3 times, the force of gravitational attraction
Solution. The force of gravitational attraction between two spherical bodies is equal to
.
When the distance between their centers increases by 3 times, the force of gravitational attraction decreases by 9 times.
Correct answer: 4.
A4. The figure shows a thin weightless rod to which forces and are applied at points 1 and 3. At what point should the axis of rotation be positioned so that the rod is in equilibrium?
| 1) | at point 2 |
| 2) | at point 6 |
| 3) | at point 4 |
| 4) | at point 5 |
Solution. The condition for equilibrium of the rod is the equality , where and are the distances from the axis of rotation to the points of application of forces. Since the second force is 3 times greater than the first, the point of its application should be located 3 times closer to the axis of rotation. This means that the axis of rotation is located either at point 2.5 or at point 4. If the axis of rotation is at point 2.5, then the forces rotate the rod in one direction and do not balance each other. When the axis of rotation is located at point 4, the forces rotate the rod in different directions, balancing each other.
Correct answer: 3.
A5. A boy threw a soccer ball weighing 0.4 kg to a height of 3 m. How much did the potential energy ball?
Solution. In general, during harmonic oscillations, the coordinate of the body changes according to the law, where A- amplitude of oscillations, ω - cyclic frequency of oscillations. The vibration amplitude is 0.9 m.
Correct answer: 3.
A7. The human ear can perceive sounds with frequencies ranging from 20 to 20,000 Hz. What wavelength range corresponds to the range of audibility of sound vibrations? Take the speed of sound in air to be 340 m/s.
| 1) | from 20 to 20000 m |
| 2) | from 6800 to 6800000 m |
| 3) | from 0.06 to 58.8 m |
| 4) | from 0.017 to 17 m |
Solution. The wavelength λ is related to the oscillation frequency ν by the relation , where v- wave propagation speed. The minimum wavelength of audible sound vibrations is
,
and the maximum wavelength of audible sound vibrations is
.
Correct answer: 4.
A8. Diffusion occurs faster as the temperature of a substance increases because
Solution. As the temperature increases, diffusion occurs faster due to an increase in the speed of particle movement.
Correct answer: 1.
A9. With a constant concentration of ideal gas particles, the average kinetic energy of thermal motion of its molecules increased by 3 times. In this case, the gas pressure
Solution. According to the basic equation of molecular kinetic theory, the pressure of an ideal gas p related to concentration n and the average kinetic energy of motion of its molecules by the ratio:
With a constant particle concentration and a 3-fold increase in their average kinetic energy, the pressure increases 3 times.
Correct answer: 2.
A10. The figure shows a graph of the dependence of gas pressure on the walls of a vessel on temperature. What process of changing the state of a gas is depicted?
Solution. The figure shows an isochoric process that went in the direction of decreasing temperature. This means that the figure shows isochoric cooling.
Correct answer: 2.
A11. When cooling a solid body with a mass m body temperature decreased by Δ T. Which of the following formulas should be used to calculate the amount of heat given off by a body? Q? c- specific heat capacity of the substance.
| 1) | |
| 2) | |
| 3) | |
| 4) |
Solution. The amount of heat given off by the body is calculated using the formula.
Correct answer: 1.
A12. Internal energy of an ideal gas during its cooling
Solution. The internal energy of an ideal gas is equal to , where is the heat capacity of the gas at constant volume, T- his temperature. The heat capacity of an ideal gas does not depend on temperature. As the temperature decreases, the internal energy of an ideal gas decreases.
Correct answer: 2.
A13. The boiling point of water depends on
Solution. Boiling of a liquid occurs at the temperature at which the saturated vapor pressure becomes equal to the external pressure. This means that the boiling point of water depends on atmospheric pressure.
Correct answer: 3.
A14. The figure shows a graph of the melting and crystallization of naphthalene. Which point corresponds to the beginning of solidification of the substance?
| 1) | point 2 |
| 2) | point 4 |
| 3) | point 5 |
| 4) | point 6 |
Solution. Solidification is the transition from a liquid to a solid state upon cooling. Cooling corresponds to part of the graph 4–7. During the solidification process, the temperature of the substance remains constant, this corresponds to part of the graph 5–6. Point 5 corresponds to the beginning of solidification of the substance.
Correct answer: 3.
A15. How will the force of the Coulomb interaction of two stationary point charges change if the distance between them is increased by n once?
Solution. The force of the Coulomb interaction of two stationary point charges is equal to
Where k- a constant value, and - the magnitude of the charges, R- the distance between them. If the distance between them is increased by n times, then the force will decrease by a factor.
Correct answer: 4.
A16. If the cross-sectional area of a homogeneous cylindrical conductor and the electrical voltage at its ends increase by 2 times, then the current flowing through it will
Solution. The current flowing through the conductor is equal to , where U- tension at its ends, R- its resistance, equal to , where ρ is the resistivity of the conductor material, l- its length, S- cross-sectional area. Thus, the current strength is . With a 2-fold increase in the voltage at its ends of the conductor and its cross-sectional area, the current flowing through it increases 4 times.
Correct answer: 3.
A17. How will the power consumed by an electric lamp change if, without changing its electrical resistance, the voltage across it is reduced by 3 times?
Solution. Power consumption is equal to , where U- voltage, R-resistance. With constant resistance and a decrease in voltage by 3 times, power consumption is reduced by 9 times.
Correct answer: 2.
A18. What needs to be done in order to change the poles of the magnetic field of a coil with current?
Solution. When the direction of the current in the coil changes, the poles of the magnetic field it generates change places.
Correct answer: 2.
A19. Will the electrical capacity of a capacitor change if the charge on its plates is increased by n once?
Solution. The electrical capacity of a capacitor does not depend on the charge on its plates.
Correct answer: 3.
A20. The oscillating circuit of the radio receiver is tuned to a radio station transmitting at a wave of 100 m. How should the capacitance of the capacitor of the oscillating circuit be changed so that it is tuned to a wave of 25 m? The inductance of the coil is considered unchanged.
Solution. The resonant frequency of the oscillatory circuit is equal to
Where C- capacitance of the capacitor, L- coil inductance. Circuit tuned to wavelength
,
Where c- speed of light. To tune a radio receiver to a four times shorter wavelength, you need to reduce the capacitance of the capacitor by 16 times.
Correct answer: 4.
A21. The camera lens is a converging lens. When you photograph an object, it produces an image on film
Solution. When photographing objects at a distance greater than the focal length of the lens, the film produces a truly inverted image.
Correct answer: 3.
A22. Two cars are moving in the same direction with speeds relative to the surface of the Earth. The speed of light from the headlights of the first car in the reference frame associated with the other car is equal to
| 1) | |
| 2) | |
| 3) | |
| 4) | c |
Solution. According to the postulate of the special theory of relativity, the speed of light is the same in all reference systems and does not depend on the speed of the source or receiver of light.
Correct answer: 4.
A23. The figure shows options for a graph of the dependence of the maximum energy of photoelectrons on the energy of photons incident on the photocathode. In what case does the graph correspond to the laws of the photoelectric effect?
| 1) | 1 |
| 2) | 2 |
| 3) | 3 |
| 4) | 4 |
Solution. An experimental study of the photoelectric effect has shown that there are frequencies at which the photoelectric effect is not observed. Only for schedule 3 there are such frequencies.
Correct answer: 3.
A24. Which of the following statements correctly describes the ability of atoms to emit and absorb energy? Isolated atoms can
Solution. Isolated atoms can emit only a certain discrete set of energies and absorb a discrete set of energies less than the ionization energy, and any portion of the energy exceeding the ionization energy.
Correct answer: none.
A25. Which of the graphs of the number of undecayed nuclei ( N) from time correctly reflects the law of radioactive decay?
Solution. According to the law of conservation of momentum, the speed of the boat will be equal to
Correct answer: 3.
A27. A heat engine with an efficiency of 40% receives 100 J from the heater per cycle. How much heat does the machine give to the refrigerator per cycle?
| 1) | 40 J |
| 2) | 60 J |
| 3) | 100 J |
| 4) | 160 J |
Solution. The efficiency of a heat engine is . The amount of heat transferred to the refrigerator per cycle is equal to .
Correct answer: 2.
A28. The magnet is removed from the ring as shown in the figure. Which magnet pole is closest to the ring?
Solution. The magnetic field created by the induction current inside the ring is directed from right to left. The ring can be considered a magnet with the north pole on the left. According to Lenz's rule, this magnet must prevent the moving magnet from moving away and, therefore, attract it. Thus, for a moving magnet, the north pole is also on the left.
Correct answer: 1.
A29. A lens made of two thin spherical glasses of the same radius, between which there is air (air lens), was lowered into water (see figure). How does this lens work?
Solution. Since the refractive index of air is less than that of water, an air lens is divergent.
Correct answer: 2.
A30. What is the binding energy of the sodium isotope nucleus? The mass of the nucleus is 22.9898 au. e.m. Round your answer to whole numbers.
| 1) | |
| 2) | |
| 3) | |
| 4) | 253 J |
Solution. The sodium isotope nucleus consists of 11 protons and 12 neutrons. The mass defect is equal to
The binding energy is
Correct answer: 2.
Part B
IN 1. A ball attached to a spring performs harmonic oscillations on a smooth horizontal plane with an amplitude of 10 cm. How much will the ball move from its equilibrium position during the time during which its kinetic energy is halved? Express your answer in centimeters and round to the nearest whole number?
Solution. In the equilibrium position, the system has only kinetic energy, and at maximum deviation - only potential energy. According to the law of conservation of energy, at the moment in time when the kinetic energy is halved, the potential energy will also be equal to half the maximum:
.
Where do we get it from:
.
AT 2. How much heat will be released when 80 g of helium is isobarically cooled from 200 °C to 100 °C? Express your answer in kilojoules (kJ) and round to the nearest whole number?
Solution. Helium is a monatomic gas with a molar mass equal to M= 4 g/mol. 80 g of helium contains 20 moles. Specific heat helium at constant pressure is equal to . Will release when cooled
AT 3. Closed resistance conductor R= 3 ohms is in a magnetic field. As a result of the change in this field, the magnetic flux penetrating the circuit increased with 
before 
. What charge passed through the cross section of the conductor? Express your answer in milliculombs (mC).
Solution. When the magnetic flux changes in a closed conductor, an emf equal to . Under the influence of this EMF, a current flows in the circuit, and during the time Δ t charge will pass through the cross section of the conductor
AT 4. While completing the experimental task, the student had to determine the period of the diffraction grating. For this purpose, he directed a light beam onto a diffraction grating through a red filter, which transmits light with a wavelength of 0.76 microns. The diffraction grating was located at a distance of 1 m from the screen. On the screen, the distance between the first-order spectra turned out to be equal to 15.2 cm. What value of the period of the diffraction grating was obtained by the student? Express your answer in micrometers (µm). (At small angles.)
Solution. Let us denote the distance from the diffraction grating to the screen R= 1 m. Deflection angles are related to the grating constant and the wavelength of light by the equality . For the first order we have:
The distance between the first order spectra on the screen is equal to
.
AT 5. Determine the energy released during the following reaction: . Express your answer in picojoules (pJ) and round to the nearest whole number.
Solution. Using tabulated data on the rest energy of the nuclei of the elements participating in the reaction, we determine the energy released:
Part C
C1. A cart with a mass of 0.8 kg moves by inertia at a speed of 2.5 m/s. A piece of plasticine weighing 0.2 kg falls vertically onto a cart from a height of 50 cm and sticks to it. Calculate the energy that was converted into internal energy during this impact.
Solution. At the moment of impact, the speed of the plasticine is equal and directed vertically downward. This speed was completely canceled out by the ground reaction force. All the kinetic energy of the fallen piece of plasticine was converted into internal energy:
At the moment of sticking of a piece of plasticine to the cart, the friction forces equalized the horizontal components of their velocities. Part of the kinetic energy of the cart was converted into internal energy. Using the law of conservation of momentum, we determine the speed of the cart with plasticine after the collision:
Converted into internal energy
As a result, the energy that became internal during this impact is equal to
Answer: 1.5 J.
C2. Some helium expands, first adiabatically and then isobarically. The final temperature of the gas is equal to the initial one. During adiabatic expansion, the gas performed work equal to 4.5 kJ. What is the work done by the gas during the entire process?
Solution. Let's depict the processes on a diagram (see figure). 1–2 - adiabatic expansion, 2–3 - isobaric expansion. According to the condition, the temperatures at points 1 and 3 are equal; the work done by the gas in process 1–2 is equal to 
. Helium is a monatomic gas, therefore its heat capacity at constant volume is equal to , where ν is the amount of substance in the gas. Using the first law of thermodynamics for process 1–2, we obtain:
The work of gas in process 2–3 can be determined by the formula. Using the Mendeleev-Clapeyron equation and equality, we obtain:
The work done by the gas during the entire process is equal to
Answer: 7.5 kJ.
C3. A small charged ball of mass 50 g, having a charge of 1 µC, moves from a height of 0.5 m along an inclined plane with an angle of inclination of 30°. At the top right angle, formed by the height and horizontal, there is a stationary charge of 7.4 μC. What is the speed of the ball at the base of the inclined plane if its initial speed is zero? Ignore friction.
Solution. The small ball is in the gravitational field of the Earth and in the electrostatic field created by the second charge. Both fields are potential, so the law of conservation of energy can be used to determine the speed of the ball. In the initial position, the ball is at a height and at a distance from the second charge. In the final position, the ball is at zero height and at a distance from the second charge. Thus:
Answer: 3.5 m/s.
C4. When a metal is irradiated with light with a wavelength of 245 nm, a photoelectric effect is observed. The work function of an electron from a metal is 2.4 eV. Calculate the amount of voltage that must be applied to the metal in order to reduce the maximum speed of emitted photoelectrons by 2 times.
Solution. The wavelength (λ) of incident light is related to its frequency (ν) by , where c- speed of light. Using Einstein's formula for the photoelectric effect, we determine the kinetic energy of photoelectrons:
Job electric field equal to . The work should be such as to reduce the maximum speed of emitted photoelectrons by 2 times:
Answer: 2 V.
C5. A vacuum diode, in which the anode (positive electrode) and cathode (negative electrode) are parallel plates, operates in a mode where the relationship between current and voltage is satisfied (where A- some constant value). How many times will the force acting on the anode due to the impact of electrons increase if the voltage on the diode is doubled? The initial speed of the emitted electrons is assumed to be zero.
Solution. When the voltage doubles, the current increases by a factor of two. The number of electrons hitting the anode per unit time will increase by the same amount. At the same time, the work of the electric field in the diode and, as a consequence, the kinetic energy of the impacting electrons will double. The speed of the particles will increase by a factor of several times, and the transmitted momentum and pressure force of individual electrons will increase by the same amount. Thus, the force acting on the anode will increase by 
times.
Final test in physics
Grade 11
1. The dependence of the coordinate on time for a certain body is described by the equation x =8t -t 2. At what point in time is the speed of the body equal to zero?
1) 8 s2) 4 s3) 3 s4) 0 s
2. With a constant concentration of ideal gas particles, the average kinetic energy of thermal motion of its molecules decreased by 4 times. In this case, the gas pressure
1) decreased by 16 times
2) decreased by 2 times
3) decreased by 4 times
4) has not changed
3. With a constant mass of an ideal gas, its pressure decreased by 2 times, and its temperature increased by 2 times. How did the volume of gas change?
1) increased by 2 times
2) decreased by 2 times
3) increased 4 times
4) has not changed
4. At constant temperature, the volume of a given mass of ideal gas increased 9 times. The pressure in this case
1) increased 3 times
2) increased 9 times
3) decreased by 3 times
4) decreased by 9 times
5. The gas in the vessel was compressed, performing 30 J of work. The internal energy of the gas increased by 25 J. Therefore, the gas
1) received from the outside an amount of heat equal to 5 J
2) gave environment amount of heat equal to 5 J
3) received from the outside an amount of heat equal to 55 J
4) gave the environment an amount of heat equal to 55 J
6. The distance between two point electric charges was increased by 3 times, and one of the charges was reduced by 3 times. Force electrical interaction between them
1) has not changed
2) decreased by 3 times
3) increased 3 times
4) decreased by 27 times
7. Current fluctuations in the circuit alternating current described by the equation I =4.cos 400πt. What is the period of current oscillation?
1) 4 c
2) 200 c
3) 0,002 c
4) 0, 005 c
8. A metal plate is illuminated with light with an energy of 6.2 eV. The work function for the metal plate is 2.5 eV. What is the maximum kinetic energy of the photoelectrons produced?
1) 3.7 eV
2) 2.5 eV
3) 6.2 eV
4) 8.7 eV
9. What is the photon energy corresponding to the light wavelength λ=6 µm?
1) 3.3. 10 -40 J
2) 4.0. 10 -39 J
3) 3.3. 10 -20 J
4) 4.0. 10 -19 J
10. The electron and proton move at the same speeds. Which of these particles has the longer de Broglie wavelength?
1) at the electron
2) at the proton
3) the wavelengths of these particles are the same
4) particles cannot be characterized by wavelength
IN 1.A body is thrown at an angle of 60 0 to the horizontal with a speed of 100 m/s. To what maximum height will the body rise? Write your answer in meters, accurate to tenths.
C1. An ideal gas first expanded at a constant temperature, then it was cooled at a constant pressure, and then heated at a constant volume, returning the gas to its original state. Draw graphs of these processes on the p-V axes. The mass of the gas did not change.
Solutions
This is the equation of uniformly accelerated motion x =x 0 +v 0x t +a x t 2 /2. The equation for speed with uniformly accelerated motion is: v x = v 0x +a x t. From the equation given to us: v 0x = 8 m/s, a x = -2 m/s 2. We supply: 0=8-2t. Where does t= 4s come from?
One of the types of the basic equation of MCT gases p = 2/3. nE k . From this equation we see that if the concentration n does not change, and the average kinetic energy of the molecules decreases by 4 times, then the pressure will decrease by 4 times.
According to the Mendeleev-Clapeyron equation pV =(m /M). RT, if the pressure decreased by 2 times and the temperature increased by 2 times, then the volume increased by 4 times.
Because the temperature and mass of the gas do not change, this is an isothermal process. For it, the Boyle-Marriott law pV = const is satisfied. From this law we see that if the volume increased 9 times, then the pressure decreased 9 times.
First law of thermodynamics: ΔU =A +Q. According to the condition, A = 30 J, ΔU = 25 J. Then, Q = -5J, i.e. the body gave up 5 J of heat to the environment.
Coulomb's law: F e =k |q 1 | . |q 2 | /r2. From this law we see that if one of the charges is reduced by 3 times, and the distance between the charges is increased by 3 times, then the electric force will decrease by 27 times.
General view of the harmonic dependence of current fluctuations: I =I m cos (ωt +φ). From the comparison we see that the cyclic frequency is ω=400π. Because ω=2πν, then the oscillation frequency is ν=200Hz. Because period T=1/ν, then T=0.005s.
Einstein's equation for the photoelectric effect: h ν = A out + E k. According to the condition, h ν = 6.2 eV, A out = 2.5 eV. Then, E k = 3.7 eV.
Photon energy E = h ν, ν = с/λ. Substituting, we get E = 3.3. 10 -20 J.
De Broglie formula: p =h /λ. Because p =mv, then mv = h /λ and λ=h /mv. Because The electron's mass is smaller and its wavelength is longer.
IN 1. Let’s take the throwing point as the reference body and direct the Y coordinate axis vertically upward. Then, the maximum height is equal to the projection of the displacement vector onto the Y axis. Let's use the formula s y =(v y 2 -v 0y 2)/(2g y). At the top point the speed is directed horizontally, so v y =0. v 0y = v 0 sinα , g y = -g . Then s y =(v 0 2 sin 2 α )/(2g ). Substituting, we get 369.8 m .
Test on the topic Molecular physics for 10th grade students with answers. The test consists of 5 options, each with 8 tasks.
1 option
A1.“The distance between neighboring particles of matter is small (they practically touch).” This statement corresponds to the model
1) only solids
2) only liquids
3) solids and liquids
4) gases, liquids and solids
A2. With a constant concentration of ideal gas particles, the average kinetic energy of thermal motion of its molecules increased by 3 times. In this case, the gas pressure
1) decreased by 3 times
2) increased 3 times
3) increased 9 times
4) has not changed
A3. What is the average kinetic energy of the chaotic translational motion of ideal gas molecules at a temperature of 27 °C?
1) 6.2 10 -21 J
2) 4.1 10 -21 J
3) 2.8 10 -21 J
4) 0.6 10 -21 J
A4. Which of the graphs shown in the figure corresponds to a process carried out at a constant gas temperature?
1) A
2) B
3) B
4) G
A5. At the same temperature, saturated steam in a closed vessel differs from unsaturated steam in the same vessel
1) pressure
2) the speed of movement of molecules
B1. The figure shows a graph of the change in pressure of an ideal gas during its expansion.
What amount of gaseous substance (in moles) is contained in this vessel if the gas temperature is 300 K? Round your answer to a whole number.
AT 2. In a vessel of constant volume there was a mixture of two ideal gases, 2 moles of each, at room temperature. Half the contents of the vessel were released, and then 2 moles of the first gas were added to the vessel. How did the partial pressures of the gases and their total pressure change as a result if the temperature of the gases in the vessel was maintained constant? For each position in the first column, select the desired position in the second.
Physical quantities
B) gas pressure in the vessel
Their change
1) increased
2) decreased
3) has not changed
C1. A piston with an area of 10 cm 2 can move without friction in a vertical cylindrical vessel, while ensuring its tightness. A vessel with a piston filled with gas rests on the floor of a stationary elevator at an atmospheric pressure of 100 kPa, while the distance from the lower edge of the piston to the bottom of the vessel is 20 cm. When the elevator moves up with an acceleration of 4 m/s 2, the piston will move by 2.5 cm. What is the mass of the piston if the change in temperature can be ignored?
Option 2
A1.“The distance between neighboring particles of matter is on average many times greater than the size of the particles themselves.” This statement corresponds
1) only models of the structure of gases
2) only models of the structure of liquids
3) models of the structure of gases and liquids
4) models of the structure of gases, liquids and solids
A2. With a constant concentration of molecules of an ideal gas, the average kinetic energy of thermal motion of its molecules changed 4 times. How did the gas pressure change?
1) 16 times
2) 2 times
3) 4 times
4) Has not changed
A3.
1) 27 °C
2) 45 °C
3) 300 °C
4) 573 °C
A4. The figure shows graphs of four processes of changes in the state of an ideal gas. Isochoric heating is a process
1) A
2) B
3) C
4) D
A5. At the same temperature, saturated water vapor in a closed vessel differs from unsaturated steam
1) concentration of molecules
2) the average speed of the chaotic movement of molecules
3) average energy of chaotic motion
4) absence of foreign gases
B1. Two vessels filled with air at a pressure of 800 kPa and 600 kPa have volumes of 3 and 5 liters, respectively. The vessels are connected by a tube, the volume of which can be neglected compared to the volumes of the vessels. Find the pressure established in the vessels. The temperature is constant.
AT 2.
Name
A) amount of substance
B) molecular mass
B) number of molecules
1) m/V
2) ν N А
3) m/N A
4) m/m
5) N/V
C1. A piston with an area of 10 cm2 and a mass of 5 kg can move without friction in a vertical cylindrical vessel, while ensuring its tightness. A vessel with a piston filled with gas rests on the floor of a stationary elevator at an atmospheric pressure of 100 kPa, while the distance from the lower edge of the piston to the bottom of the vessel is 20 cm. What will this distance be when the elevator moves down with an acceleration equal to 3 m/s 2? Ignore changes in gas temperature.
Option 3
A1.“Particles of matter participate in continuous thermal chaotic motion.” This position of the molecular kinetic theory of the structure of matter refers to
1) gases
2) liquids
3) gases and liquids
4) gases, liquids and solids
A2. How will the pressure of an ideal monatomic gas change when the average kinetic energy of thermal motion of its molecules increases by 2 times and the concentration of molecules decreases by 2 times?
1) Will increase 4 times
2) Will decrease by 2 times
3) Will decrease by 4 times
4) Will not change
A3. What is the average kinetic energy of the chaotic translational motion of ideal gas molecules at a temperature of 327 °C?
1) 1.2 10 -20 J
2) 6.8 10 -21 J
3) 4.1 10 -21 J
4) 7.5 kJ
A4. On VT The diagram shows graphs of changes in the state of an ideal gas. Isobaric process corresponds to the graph line
1) A
2) B
3) B
4) G
A5. In a vessel containing only steam and water, the piston is moved so that the pressure remains constant. The temperature in this case
1) does not change
2) increases
3) decreases
4) can either decrease or increase
B1. Two vessels with volumes of 40 or 20 liters contain gas at the same temperatures but different pressures. After connecting the vessels, a pressure of 1 MPa was established in them. What was the initial pressure in the larger vessel if the initial pressure in the smaller vessel was 600 kPa? The temperature is assumed to be constant.
AT 2. In a vessel of constant volume there was a mixture of two ideal gases, 2 moles of each, at room temperature. Half the contents of the vessel were released, and then 2 moles of a second gas were added to the vessel. How did the partial pressures of the gases and their total pressure change as a result if the temperature of the gases in the vessel was maintained constant?
For each position in the first column, select the desired position in the second.
Physical quantities
A) partial pressure of the first gas
B) partial pressure of the second gas
B) gas pressure in the vessel
Their change
1) increased
2) decreased
3) has not changed
C1. A piston weighing 5 kg can move without friction in a vertical cylindrical vessel, ensuring its tightness. A vessel with a piston filled with gas rests on the floor of a stationary elevator at an atmospheric pressure of 100 kPa, while the distance from the lower edge of the piston to the bottom of the vessel is 20 cm. When the elevator moves down with an acceleration equal to 2 m/s 2, the piston will move by 1.5 cm. What is the area of the piston if the change in gas temperature is not taken into account?
Option 4
A1. In liquids, particles oscillate near an equilibrium position, colliding with neighboring particles. From time to time the particle makes a jump to a different equilibrium position. What property of liquids can be explained by this nature of particle motion?
1) Low compressibility
2) Fluidity
3) Pressure on the bottom of the vessel
4) Change in volume when heated
A2. As a result of cooling of a monatomic ideal gas, its pressure decreased by 4 times, but the concentration of gas molecules did not change. In this case, the average kinetic energy of thermal motion of gas molecules
1) decreased by 16 times
2) decreased by 2 times
3) decreased by 4 times
4) has not changed
A3. The average kinetic energy of translational motion of gas molecules in a cylinder is 4.14 · 10 -21 J. What is the temperature of the gas in this cylinder?
1) 200 °C
2) 200 K
3) 300 °C
4) 300 K
A4. The figure shows a cycle carried out with ideal gas. Isobaric heating corresponds to the area
1) AB
2) DA
3) CD
4) BC
A5. When the volume of saturated steam decreases at a constant temperature, its pressure
1) increases
2) decreases
3) for some vapors it increases, and for others it decreases
4) does not change
B1. The figure shows a graph of the dependence of gas pressure in a sealed vessel on its temperature.
The volume of the vessel is 0.4 m3. How many moles of gas are contained in this container? Round your answer to a whole number.
AT 2. Match the name physical quantity and a formula by which it can be determined.
Name
A) concentration of molecules
B) number of molecules
B) molecular mass
1) m/V
2) ν N А
3) m/N A
4) m/m
5) N/V
C1. A piston with an area of 15 cm2 and a mass of 6 kg can move without friction in a vertical cylindrical vessel, while ensuring its tightness. A vessel with a piston filled with gas rests on the floor of a stationary elevator at an atmospheric pressure of 100 kPa. In this case, the distance from the lower edge of the piston to the bottom of the vessel is 20 cm. When the elevator begins to move upward with acceleration, the piston moves by 2 cm. With what acceleration does the elevator move if the change in gas temperature can be ignored?
Option 5
A1. The least order in the arrangement of particles is characteristic of
1) gases
2) liquids
3) crystalline bodies
4) amorphous bodies
A2. How will the pressure of an ideal monatomic gas change if the average kinetic energy of thermal motion of molecules and the concentration are reduced by 2 times?
1) Will increase 4 times
2) Will decrease by 2 times
3) Will decrease by 4 times
4) Will not change
A3. At what temperature is the average kinetic energy of translational motion of gas molecules equal to 6.21 · 10 -21 J?
1) 27 K
2) 45 K
3) 300 K
4) 573 K
A4. The figure shows a cycle carried out with an ideal gas. Isobaric cooling corresponds to the area
1) AB
2) DA
3) CD
4) BC
A5. The vessel under the piston contains only saturated water vapor. How will the pressure in the vessel change if you begin to compress the vapor, maintaining the temperature of the vessel constant?
1) The pressure will constantly increase
2) The pressure will constantly drop
3) The pressure will remain constant
4) The pressure will remain constant and then begin to fall
B1. On the image. shows a graph of the isothermal expansion of hydrogen.
The mass of hydrogen is 40 g. Determine its temperature. The molar mass of hydrogen is 0.002 kg/mol. Round your answer to a whole number.
AT 2. Establish a correspondence between the name of a physical quantity and the formula by which it can be determined.
Name
A) density of matter
B) amount of substance
B) molecular mass
1) N/V
2) ν N А
3) m/N A
4) m/m
5) m/V
C1. A piston with an area of 10 cm2 and a mass of 5 kg can move without friction in a vertical cylindrical vessel, while ensuring its tightness. A vessel with a piston filled with gas rests on the floor of a stationary elevator at an atmospheric pressure of 100 kPa, while the distance from the lower edge of the piston to the bottom of the vessel is 20 cm. What will this distance be when the elevator moves up with an acceleration equal to 2 m/s 2? Ignore changes in gas temperature.
Answers to test on the topic Molecular physics grade 10
1 option
A1-3
A2-2
A3-1
A4-3
A5-1
IN 1. 20 mol
AT 2. 123
C1. 5.56 kg
Option 2
A1-1
A2-3
A3-1
A4-3
A5-1
IN 1. 675 kPa
AT 2. 432
C1. 22.22 cm
Option 3
A1-4
A2-4
A3-1
A4-1
A5-1
IN 1. 1.2 MPa
AT 2. 213
C1. 9.3 cm 2
Option 4
A1-2
A2-3
A3-2
A4-1
A5-4
IN 1. 16 mol
AT 2. 523
C1. 3.89 m/s 2
Option 5
A1-1
A2-3
A3-3
A4-3
A5-3
IN 1. 301 K
AT 2. 543
C1. 18.75 cm
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