Q. No.Two cylinders, \(A\) and \(B,\) of equal capacity are connected to each other via a stopcock. \(A\) contains gas at a standard temperature and pressure \(B\) is completely evacuated. The entire system is thermally insulated. If the stopcock is suddenly opened, then the change in internal energy of the gas is:
1. \(0\)
2. \(5~\text{J}\)
3. \(1~\text{J}\)
4. \(3~\text{J}\)
(where symbols have their usual meanings)
1. \(C_P = \frac{\gamma R}{\gamma-1 }\)
2. \(C_P-C_V= R\)
3. \(\Delta U = \frac{P_fV_f-P_iV_i}{1-\gamma}\)
4. \(C_V = \frac{R}{\gamma-1 }\)
The pressure and volume of a gas are changed as shown in the P-V diagram. The temperature of the gas will:
| 1. | increase as it goes from A to B. |
| 2. | increase as it goes from B to C. |
| 3. | remain constant during these changes. |
| 4. | decrease as it goes from D to A. |
Find out the total heat given to diatomic gas in the process \(A\rightarrow B \rightarrow C\): \(( B\rightarrow C\) is isothermal)
1. \(P_0V_0+ 2P_0V_0\ln 2\)
2. \(\frac{1}{2}P_0V_0+ 2P_0V_0\ln 2\)
3. \(\frac{5}{2}P_0V_0+ 2P_0V_0\ln 2\)
4. \(3P_0V_0+ 2P_0V_0\ln 2\)
Consider a cycle followed by an engine (figure).
1 to 2 is isothermal,
2 to 3 is adiabatic,
3 to 1 is adiabatic.
Such a process does not exist, because:
| (a) | heat is completely converted to mechanical energy in such a process, which is not possible. |
| (b) | In this process, mechanical energy is completely converted to heat, which is not possible. |
| (c) | curves representing two adiabatic processes don’t intersect. |
| (d) | curves representing an adiabatic process and an isothermal process don't intersect. |
Choose the correct alternatives:
| 1. | (a), (b) | 2. | (a), (c) |
| 3. | (b), (c) | 4. | (c), (d) |
The standard enthalpies of the formation of NO2(g) and N2O4(g) are 8 kcal mol–1 and 2 kcal mol–1 respectively. The heat of dimerization of NO2 in the gaseous state is:
| 1. | 10 k cal mol–1 | 2. | 6.0 k cal mol–1 |
| 3. | –14 k cal mol–1 | 4. | –6.0 k cal mol–1 |
\(0.04\) mole of an ideal monatomic gas is allowed to expand adiabatically so that its temperature changes from \(800~\text{K}\) to \(500~\text{K}.\) The work done during expansion is nearly equal to:
| 1. | \(129.6~\text J\) | 2. | \(-129.6~\text J\) |
| 3. | \(149.6~\text J\) | 4. | \(-149.6~\text J\) |
1. \(V_1= V_2\)
2. \(V_1> V_2\)
3. \(V_1< V_2\)
4. \(V_1\ge V_2\)
1. \(5:3\)
2. \(5:2\)
3. \(1:1\)
4. \(5:7\)
A system that can neither exchange matter nor energy with the surroundings is classified as:
1. Open system
2. Isolated system
3. Closed system
4. Both (1) & (2)
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