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First Law Of Thermodynamics - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • First law of Thermodynamics is considered one of the most asked concept.

  • 45 Questions around this concept.

Solve by difficulty

Which of the following is incorrect regarding the first law of thermodynamics?

In a given process of an ideal gas dW=0 and dQ<0. Then for the gas

An ideal gas is taken via path as shown in figure. The net work done in the whole cycle is

First law of thermodynamics provides a relation between these quantities


 

The correct 1st law equation for the isothermal process will be

A total of $48 \mathrm{~J}$ heat is given to one mole of helium kept in a cylinder. The temperature of helium increases by $2^{\circ} \mathrm{C}$. The work done by the gas is : (Given, $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$.)

Direction:  In the following question, a statement of Assertion (A)  is followed by a statement of reason (R). Mark the correct choice as: 

Assertion: First law of thermodynamics states that energy is conserved.

Reason: According to the first laws of thermodynamics SW=SQ+dv

 

 

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A thermodynamic system of mono-atomic gas uses half of the heat given in work done. Find out the process equation.
 

During the melting of a slab of ice at 273 K at atmospheric pressure :

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Concepts Covered - 1

First law of Thermodynamics

First law of thermodynamics - 

According to it heat given to a system (Q) is equal to the sum of increase in its internal energy (U) and the work done (W) by the system against the surroundings.

                             

$$
\Delta Q=\Delta U+\Delta W
$$

or For cyclic process

$$
\sum \Delta Q=\sum \Delta W
$$
 

 

Drawback of First law of thermodynamics -

  • First law of thermodynamics does not tell us reason about the direction of heat transfer.

 

Important points - 

  1. Q and W are the path functions but U is the point function.

  2. First law of thermodynamics introduces the concept of internal energy.

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First law of Thermodynamics

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Books

Reference Books

First law of Thermodynamics

Physics Part II Textbook for Class XI

Page No. : 307

Line : 51

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