2
The thermal efficiency of an ideal air-standard Otto cycle is 0.5 . The value of specific heat ratio of air is 1.4. The compression ratio of the cycle is _________ (rounded off to 1 decimal place).
4
A heat engine extracts heat (๐H) from a thermal reservoir at a temperature of 1000 K and rejects heat (๐L) to a thermal reservoir at a temperature of 100 K, while producing work (๐). Which one of the combinations of [๐H, ๐L and ๐] given is allowed?
5
The Clausius inequality holds good for
6
A heat pump absorbs $$10$$ $$kW$$ of heat from outside environment at $$250$$ $$K$$ while absorbing $$15$$ $$kW$$ of work. It delivers the heat to a room that must be kept warm at $$300$$ $$K.$$ The Coefficient of performance $$(COP)$$ of the heat pump is _____________.
7
The heat removal rate from a refrigerated space and the power input to the compressor are $$7.2$$ $$kW$$ and $$1.8$$ $$kW$$, respectively. The coefficient of performance $$(COP)$$ of the refrigerator is ___________
8
The $$COP$$ of a Carnot heat pump operating between $${6^ \circ }C$$ and $${37^ \circ }C$$ is ____________
9
A Carnot engine $$(CE$$-$$1)$$ works between two temperature reservoirs $$A$$ and $$B,$$ where $${T_A} = 900K$$ and $${T_B} = 500K.$$ A second Carnot engine $$(CE$$-$$2)$$ works between temperature reservoirs $$B$$ and $$C,$$ where $${T_c} = 300\,\,K.$$ In each cycle of $$CE$$-$$1$$ and $$CE$$-$$2,$$ all the heat rejected by $$CE$$-$$1$$ to reservoir $$B$$ is used by $$CE$$-$$2.$$ For one cycle operation, if the net $$Q$$ absorbed by $$CE$$-$$1$$ from reservoir $$A$$ is $$150$$ $$MJ,$$ the net heat rejected to reservoir $$C$$ by $$CE$$-$$2$$ (in $$MJ$$) is ______________
10
A reversed Carnot cycle refrigerator maintains a temperature of $$ - {5^ \circ }C.$$ The ambient air temperature is $${35^ \circ }C.$$ The heat gained by the refrigerator at a continuous rate is $$2.5$$$$kJ/s.$$ The power (in watt) required to pump this heat out continuously is _____________.
12
An industrial heat pump operates between the temperatures of $${27^ \circ }C$$ and $$ - {13^ \circ }C.$$ The rates of heat addition and heat rejection are $$750$$ $$W$$ and $$1000$$ $$W,$$ respectively. The $$COP$$ for the heat pump is
13
Consider a refrigerator and a heat pump working on the reversed Carnot cycle between the same temperature limits. Which of the following is correct?
14
In the case of a refrigeration system undergoing an irreversible cycle, $$\oint {{{SQ} \over T}} $$ is _____________$$\left( { < 0/ = 0/ > 0} \right)$$
15
Any thermodynamic cycle operating between two temperature limits is reversible if the product of efficiency when operating as a heat engine and the coefficient of performance when operating as a refrigeration is equal to $$1.$$
16
A reversible heat transfer demands:
17
A condenser of a refrigeration system rejects heat at a rate of $$120$$ $$kW,$$ while its compressor consumes a power of $$30$$ $$kW.$$ The coefficient of performance of the system would be