1st Law of Thermodynamics

Q. Find the value of $\Delta U$.

1. +150 J
2. -50 J
3. +50 J
4. -150 J

Q.

Match the following:

$1.W_{AB}$ $I.0$
$2.W_{BC}$ $II.-1500J$
$3.W_{CA}$ $III.1000J$

1. $1-II,2-I,3-III$
2. $1-I,2-II,3-III$
3. $1-III,2-I,3-II$
4. $1-III,2-II,3-I$

Q. Find the value of \(\Delta U\).


\( K_{Q=50 J } \quad 30 J \)

Q. One mole of an ideal monatomic gas requires 210 J heat to raise the temperature by 10 K, when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by 10 K then heat required is

1. 238 J
2. 210 J
3. 126 J
4. 350 J

Q. An ideal gas undergoes an expansion from a state with temperature $T_1$ and volume $V_1$ through three different polytropic process A, B and C as shown in the $P-V$ diagram. If $|\Delta E_A|,|\Delta E_B|$ and $|\Delta E_C|$ be the magnitude of changes in internal energy along the three paths respectively, then

1. $|\Delta E_A|<|\Delta E_B|<|\Delta E_C|$ if temperature in every process decreases
2. $|\Delta E_B|<|\Delta E_A|<|\Delta E_C|$ if temperature in every process increases
3. $|\Delta E_A|>|\Delta E_B|>|\Delta E_C|$ if temperature in every process increases
4. $|\Delta E_A|>|\Delta E_B|>|\Delta E_C|$ if temperature in every process decreases

Q.

An experimenter adds 970 J of heat to 1.75 mol of an ideal gas to heat it from ${10.0}^{\circ }C$ to ${25.0}^{\circ }C$ at constant pressure. The gas does +223 J of work during the expansion. (i) Calculate the change in internal energy of the gas. (ii) Calculate $\gamma$ for the gas.

1. 859 J; 1.81

2. 747 J; 2.37

3. 650 J ; 1.29

4. 747 J ; 1.29

Q.

A system is any specified portion of matter which is separated from the rest of the universe with a definite boundary. (T/F)

1. True

2. False

Q.

Water contained in a metallic water bottle is an example of:

1. Isolated system

2. Open system

3. None

4. Closed system

Q. An insulator container contains 4 moles of an ideal diatomic gas at temperature T. Heat Q is supplied to this gas, due to which 2 moles of the gas are dissociated into atoms but temperature of the gas remains constant. Then

1. Q=RT
2. Q=3RT
3. Q=4RT
4. Q=2RT

Q. Following figure shows on adiabatic cylindrical container of volume V_o divided by an adiabatic smooth piston (area of cross-section = A) in two equal parts. An ideal gas is at pressure P₁ and temperature T₁ in left part and gas at pressure P₂ and temperature T₂ in right part. The piston is slowly displaced and released at a position where it can stay in equilibrium. The final pressure of the two parts will be (Suppose x = displacement of the piston)

1. 
2. 
3. 
4.