Physics

Thermodynamics and Gas Laws

626 Questions

Thermodynamics and gas laws questions test the understanding of ideal gas behavior, work done during thermodynamic processes, and specific heat ratios. Key areas include isothermal, adiabatic, and isobaric expansions along with real gas deviations. These mathematical physics concepts are standard in engineering and general science competitive exams.

Ideal gas equationIsothermal and adiabatic processesThermodynamic workGas kinetic theoryReal gas behavior

Thermodynamics and Gas Laws Questions

Multiple choice

Gases are highly compressible due to

  1. large intermolecular space

  2. high kinetic energy

  3. strong forces

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gases are highly compressible due to large intermolecular space.  When force of attraction is strong in the gases molecules, then gases start to liquefy. For eg. LPG is such a gas.

Multiple choice

Volume of a gas is increased by increasing its

  1. pressure

  2. adding more gas

  3. boiling point

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Volume of the gas increases when we increase the temperature of the gas. It is due to the reason that the force of attraction present in the molecules of gas start decreasing with the increase in the temperature, so gas molecules starts expanding or the distance between them start increasing.

Multiple choice

What is the perfect gas equation for one mole of a perfect gas?

  1. PV = nRT

  2. V/T = constant

  3. PV = RT

  4. pV = constant
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In perfect or ideal gas the change in density is directly related to the change of temperature and pressure as expressed by the Ideal Gas Law. PV=RT is the gas equation for one mole of gas.

Multiple choice

Which of the following is not true in case of high pressure gas welding?

  1. The work surface is melted and joining is done by pressure.

  2. Gas is stored in cylinder at high pressure.

  3. Equal-pressure type welding torch is used.

  4. Gas pressure is regulated as per thickness of the work.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

High pressure gas welding is a fusion welding process where the metal is melted by a gas flame. It does not rely on pressure to join the metals, unlike forge welding.

Multiple choice

The Van der Wall's equation explains the behaviour of ___.

  1. ideal gases

  2. real gases

  3. gobar gases

  4. elementary gases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Van der Waals equation is a modification of the ideal gas law that accounts for the non-zero volume of gas molecules and the intermolecular forces present in real gases.

Multiple choice

A Gas has

  1. Definite volume and no definite shape

  2. No definite volume no definite shape

  3. Definite shape and volume

  4. Definite shape but no definite volume
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A Gas has No definite volume no definite shape

Multiple choice

The Van der Waal' s equation reduces itself to the ideal gas equation at

  1. high pressure & low temperature

  2. low pressure & low temperature

  3. low pressure & high temperature

  4. high pressure & high temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Real gases behave most like ideal gases under conditions of low pressure and high temperature. At low pressure, intermolecular distances are large, and at high temperature, kinetic energy overcomes intermolecular attractions.

Multiple choice

Why does the pressure of car tires increase after driving?

  1. Air molecules break up to form separate atoms

  2. The force between air molecules increase

  3. Air molecules expand

  4. The speed of the air molecule increase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

As the tire heats up from friction while driving, the kinetic energy of the air molecules increases. According to the kinetic theory of gases, higher molecular speed results in more frequent and forceful collisions with the tire walls, increasing pressure.

Multiple choice

Boyle's law is applicable at ________.

  1. constant pressure

  2. constant temperature

  3. constant temperature and pressure

  4. variable temperature

  5. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Boyle's Law states that for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional. Therefore, temperature must be constant.