Physics #restart (Thermodynamics SET C -Medium)Contact Number: 8527521718Physics #restart (Thermodynamics SET C -Medium)Contact Number: 8527521718
A monoatomic gas is supplied with the heat \(Q\) very slowly, keeping the pressure constant. The work done by the gas will be:
1. \({2 \over 3}Q\)
2. \({3 \over 5}Q\)
3. \({2 \over 5}Q\)
4. \({1 \over 5}Q\)
At a pressure of \(2\) atmospheres, a mass of diatomic gas \((\gamma = 1.4)\), is compressed adiabatically, causing its temperature to rise from \(27^{\circ}\mathrm{C}\) to \(927^{\circ}\mathrm{C}\). The pressure of the gas in the final state is:
1. 8 atm
2. 28 atm
3. 68.7 atm
4. 256 atm
\(0.04\) 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. | \(-149.6~\text J\) |
The volume \((V)\) of a monatomic gas varies with its temperature \((T),\) as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state \(A\) to state \(B\) will be:
| 1. | \(\dfrac{2}{5}\) | 2. | \(\dfrac{2}{3}\) |
| 3. | \(\dfrac{1}{3}\) | 4. | \(\dfrac{2}{7}\) |
An ideal gas is enclosed in an insulated cylinder. The piston is frictionless and attached to an ideal spring. When the gas is heated, then:
| 1. | the work is done against the spring only. |
| 2. | the work is done against the atmospheric pressure only. |
| 3. | the internal energy of gas increases. |
| 4. | the work is equal to the heat supplied. |
A cyclic process for \(1\) mole of an ideal gas is shown in the \(V\text-T\) diagram. The work done in \(AB, BC\) and \(CA\) respectively is:
| 1. | \(0, R T_2 \ln \left(\frac{V_1}{V_2}\right), R\left(T_1-T_2\right)\) |
| 2. | \(R\left(T_1-T_2\right), 0, R T_1 \ln \frac{V_1}{V_2}\) |
| 3. | \(0, R T_2 \ln \left(\frac{V_2}{V_1}\right), R\left(T_1-T_2\right)\) |
| 4. | \(0, R T_2 \ln \left(\frac{V_2}{V_1}\right), R\left(T_2-T_1\right)\) |
A sink, that is, the system where heat is rejected, is essential for the conversion of heat into work. From which law does the above inference follow?
1. Zeroth
2. First
3. Second
4. Third
When the sink temperature is kept at \(400~\text{K},\) the efficiency of a Carnot engine is \(50\text{%}.\) While keeping the source temperature constant, by how much should we reduce the sink temperature to increase the efficiency to \(60\text{%}\text{?}\)
| 1. | \(80\) K | 2. | \(70\) K |
| 3. | \(320\) K | 4. | \(240\) K |
In isothermal expansion, the pressure is determined by:
| 1. | Temperature only |
| 2. | Compressibility only |
| 3. | Both temperature and compressibility |
| 4. | None of these |
The pressure of a monoatomic gas increases linearly from \(4\times 10^5~\text{N/m}^2\) to \(8\times 10^5~\text{N/m}^2\) when its volume increases from \(0.2 ~\text m^3\) to \(0.5 ~\text m^3.\) The work done by the gas is:
1. \(2 . 8 \times10^{5}~\text J\)
2. \(1 . 8 \times10^{6}~\text J\)
3. \(1 . 8 \times10^{5}~\text J\)
4. \(1 . 8 \times10^{2}~\text J\)
