The variation of pressure versus temperature of an ideal gas is shown in the given diagram. From this diagram, one can conclude that
1. | Volume increases continuously |
2. | Volume decreases continuously |
3. | Volume first increases then decreases |
4. | Volume first decreases, then increase |
A carnot engine having an efficiency of th of heat engine, is used as a refrigerator. If then work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is:
1. 1 J
2. 90 J
3. 99 J
4. 100 J
The temperature inside a refrigerator is and the room temperature is . The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be:
1.
2.
3.
4.
The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20°C, the temperature of the surroundings to which it rejects heat is -
1. 31°C
2. 41°C
3. 11°C
4. 21°C
One mole of an ideal gas at an initial temperature of T K does 6R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of the gas will be:
1. | (T + 2.4)K | 2. | (T – 2.4)K |
3. | (T + 4)K | 4. | (T – 4)K |
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 = 2RT
2. Q = RT
3. Q = 3RT
4. Q = 4RT
P-V diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be -
1. 4 R
2. 2.5 R
3. 3 R
4.
The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is
1. 1/3
2. 2/3
3. 1/2
4. 1/4
When a system is taken from state i to a state f along path iaf, Q = 50 J and W = 20 J.
If W = –13 J for the curved return path fi, Q for this path is -
1. 33 J
2. 23 J
3. – 7 J
4. – 43 J
An ideal gas is taken from point A to the point B, as shown in the P-V diagram. The work done in the process is -
1.
2.
3.
4.
Thermodynamic processes are indicated in the following diagram:
Match the following:
Column-I | Column-II | ||
(P) | Process I | (a) | Adiabatic |
(Q) | Process II | (b) | Isobaric |
(R) | Process III | (c) | Isochoric |
(S) | Process IV | (d) | Isothermal |
1. | P → c, Q → a, R → d, S→ b |
2. | P→ c, Q → d, R → b, S → a |
3. | P → d, Q → b, R → b, S → c |
4. | P → a, Q → c, R → d, S → b |
One mole of an ideal monatomic gas undergoes a process described by the equation \(PV^3=\text{constant}.\) The heat capacity of the gas during this process is:
1. \(\frac{3}{2}R\)
2. \(\frac{5}{2}R\)
3. \(2R\)
4. \(R\)
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 engine has an efficiency of . When the temperature of the sink is reduced by , its efficiency is doubled. the temperature of the source is:
1. 124oC
2. 37oC
3. 62oC
4. 99oC