B Circle the right answer only one answer is correct 1 The c

B) Circle the right answer (only one answer is correct):
1. The correct Kelvin-Planck statement of the second law is:
a. A refrigerator can transfer heat from a low-temperature reservoir to high temperature reservoir without work.
b. A heat engine can reject more heat than the heat it receives.
c. A heat engine cannot produce net work without rejecting heat to a low temperature reservoir.
d. A heat engine reject heat if the net work is less than the heat it receives.

2. In a throttling process by an adiabatic throttling valve in a refrigeration cycle:
a. The pressure drops but specific internal energy remains almost constant.
b. The pressure increases and the temperature decreases.
c. The pressure decreases but the specific enthalpy remains almost constant.
d. The entropy decreases due to internal irreversibility.

considering the same device as a heat pump or refrigerator, one of the following statements is valid:
a. Coefficient of performance of refrigerator (COP)R is higher than that for heat pump (COP)HP.
b. Coefficient of performance of heat pump (COP)HP is higher than that for refrigerator (COP)R.
c. Coefficient of performance of refrigerator (COP)R is equal to that for heat pump (COP)HP.
d. There is no relation between (COP)R and (COP)HP.

Solution

Question B-1: Ans is option (D) : only some part of the energy received is converted into work.

B-2: option(A) : throttling is a isenthalphy process but pressure decreases.

B-3 option(B) : Coefficient of performance of heat pump (COP)HP is equal to one plus to the refrigerator (COP)R