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Punjab (PTB) · Chapter test · Free

2nd Year Physics Chapter 1 TestTHERMAL PHYSICS

30 marks · 40 minutes · 21 questions. Covers: CHAP 13: THERMAL PHYSICS.

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2nd Year Physics Chapter 1 Test

2nd Year · Physics · Punjab (PTB)

Name: ____________Roll No: ________Class/Section: ________Date: ________Total marks: 30Time: 40 minutes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

  1. According to the kinetic theory, gas pressure arises due to particles interacting with each other and what else?

    1. The volume of the container

    2. The walls of the container

    3. The absolute zero temperature

    4. External atmospheric forces

  2. In highly massive stars, successive fusion stages continue until the core forms increasingly complex nuclei up to which element?

    1. Helium

    2. Carbon

    3. Oxygen

    4. Iron

  3. As a molecular cloud contracts to form a proto-star, its density and temperature increase due to a rise in the:

    1. Kinetic energy of particles

    2. Chemical energy of dust

    3. Gravitational constant

    4. Total volume

  4. Rapidly rotating neutron stars that emit regular beams of radiation are called:

    1. Black holes

    2. White dwarfs

    3. Pulsars

    4. Protostars

  5.  What is exchanged between molecules during their continuous collisions?

    1. Momentum and energy

    2. Mass and charge

    3. Viscosity and friction

    4. Gravity and volume

  6. According to estimates by NASA, how many neutron stars may exist within the Milky Way galaxy?

    1. Up to a million

    2. Up to a billion

    3. Up to a trillion

    4. Up to a quadrillion

  7. In 1860, who derived the expression describing the distribution of molecular speeds at thermal equilibrium?

    1. Ludwig Boltzmann

    2. James Clerk Maxwell

    3. Robert Brown

    4. J. Perrin

  8. What is the average distance a moving particle covers before it undergoes a collision that significantly alters its direction?

    1. Displacement path

    2. Mean free path

    3. Elastic path

    4. Random path

  9. According to Newton's second law of motion, force is equal to the:

    1. Rate of change of momentum

    2. Product of mass and velocity

    3. Product of pressure and volume

    4. Total kinetic energy divided by area

  10. One electron volt (eV) is defined as the kinetic energy of an electron accelerated through a potential difference of:

    1.  One volt

    2. 300 volts

    3. Avogadro's number of volts

    4. None of these

Q2. Short questions (Attempt any 6 of 8 · 6 × 2 = 12)

  1. What is the assumption regarding forces of attraction or repulsion between gas particles?

  2. Consider a gas enclosed in a sealed container. By what factor does the gas temperature change if: (a) the volume and pressure are both doubled? (b) the volume is halved and the pressure is tripled?

  3. Define thermal physics.

  4. What is the final fate of low and intermediate-mass stars once their nuclear fuel is exhausted?

  5. How is the temperature of a gas related to the motion of its molecules?

  6. What are the two possibilities if the balance between pressure force and gravitational force is not maintained in a star?

  7. Define one electron volt (eV) and write its value in Joules.

  8. Express the total pressure P on a wall due to N molecules with different speeds in the x-direction.

Q3. Long questions (Attempt any 2 of 3 · 2 × 4 = 8)

  1. Show that temperature of a gas is a direct measure of the average translational K.E. of its molecules.

  2. A star has a mass enclosed within radius r equal to 2.0 x 1030 Kg, density 1500 Kg m-3 and radius 7.0 x 108 m. Calculate the gravitational force inside the star.

  3. At what temperature will the rms speed of the molecules of gas be three times its value at STP?