Tag: zeroth law of thermodynamics

Questions Related to zeroth law of thermodynamics

Two bodies A and B are said to be in thermal equilibrium with each other, if :

physics heat and energy zeroth law of thermodynamics

  1. heat flows from A to B

  2. heat flows from B to A

  3. both the bodies lose equal amounts of heat to the atmosphere

  4. heat does not flow from either A or B

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Correct Option: D
Explanation:

The correct answer is option(D).

Thermal equivalence happens when there is no temperature difference between two bodies. And no heat transfer happens.

For 2 gases in thermal equilibrium with each other , Pressure of the gases 

physics heat and energy zeroth law of thermodynamics

  1. varies as speed of the gas molecules

  2. varies as square root of the gas molecules

  3. varies inversely as the gas molecules

  4. remains same

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Correct Option: D
Explanation:

For the ideal gas equation $PV=nRT$

if T is constant the pressure is also constant
hence  when the gases in thermal equilibrium have same temperature their pressure remains same .
 hence option D is correct.

Two systems are in thermal equilibrium. The quantity which is common for them is

physics heat and energy zeroth law of thermodynamics

  1. heat

  2. momentum

  3. specific heat

  4. temperature

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Correct Option: D
Explanation:

Thermal equilibrium implies that there is no heat transfer taking place between the given two bodies i.e. there temperature is same.

When a gas  is in thermal equilibrium, its molecules

physics heat and energy zeroth law of thermodynamics

  1. have the same average kinetic energy.

  2. have different energies which remains constant.

  3. have a certain constant energy.

  4. do not collide with one another.

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Correct Option: A
Explanation:

When a gas is in thermal equilibrium, the temperature throughout the gas is the same. (Zeroth law of thermodynamics)
The average kinetic energy of the gas molecules is directly proportional to the absolute temperature of the gas. I.e. different sections of the gas will all have the same average kinetic energy.

Two metal spheres of different radii having same temperature are placed in thermal contact in a vaccum. Which of the following quantities is certainly correct?

physics heat and energy zeroth law of thermodynamics

  1. Each sphere has the same internal energy

  2. There is no net transfer of thermal energy between the spheres

  3. Both spheres radiate electromagnetic energy at the same rate

  4. The larger sphere a greater mean internal energy per atom than the smaller sphere

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Correct Option: B
Explanation:

There is no net transfer of thermal energy between the spheres.

Option B is correct.

Two bodies are in thermal equilibrium if they have same

physics heat and energy zeroth law of thermodynamics

  1. temperature

  2. amount of heat

  3. specific heat

  4. thermal capacity

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Correct Option: A
Explanation:

Thermal equilibrium means that there is no heat transfer going on between the bodies, which simply means that the bodies are at the same temperature. Heat content is a whole different concept - it is the amount of heat contained in a body, which is crucially dependent on mass. 

Two bodies A and B are said to be in thermal equilibrium with each other, if

physics heat and energy zeroth law of thermodynamics

  1. heat flows from A to B

  2. heat flows from B to A

  3. both the bodies lose equal amunts of heat to the atmosphere

  4. heat does not flow from either A or B

Show answer
Correct Option: D
Explanation:

Two bodies A and B are said to be in thermal equilibrium with each other, ifheat does not flow from either A or B 

Two systems in thermal equilibrium with a third system separately are in thermal equilibrium with each other.
The above statement is

physics heat and energy zeroth law of thermodynamics

  1. First law of thermodynamics

  2. Second law of thermodynamics

  3. Third law of thermodynamics

  4. Zeroth law of thermodynamics

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Correct Option: D
Explanation:

The given statement is the exact statement of Zeroth law of thermodynamics which deals with thermal equilibrium.

Three bodies $A, B$ and $C$ are in thermal equilibrium.
The temperature of $B$ is $45^{\circ}C$. Then the temperature of $'C'$ is _____

physics heat and energy zeroth law of thermodynamics

  1. $45^{\circ}C$

  2. $50^{\circ}C$

  3. $40^{\circ}C$

  4. Any temperature

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Correct Option: A
Explanation:

A, B and C are in thermal equilibrium and B is at temperature $45^0 C$, then according to zeroth law of thermodynamics both A and C will also be at temperature $45^0 C$.

If the output energy is$ 1000 J$ and input energy is $200 J $the net output is _____ $J$.

physics heat and energy zeroth law of thermodynamics

  1. $800$

  2. $1200$

  3. $10$

  4. $500$

Show answer
Correct Option: A
Explanation:

The net output $=$ output - input
$= 1000 - 200 = 800 J$