(Detailed solution) IES 2016 | Thermodynamics Questions

IES 2016 Thermodynamics Questions

Question #1

Which of the following statements are correct for a throttling process?

1. It is an adiabatic steady flow process

2. The enthalpy before and after throttling is same.

3. In the process, due to fall in pressure, the fluid velocity at outlet is always more than inlet velocity

(A) 1 and 2 only

(B) 1 and 3 only

(C) 2 and 3 only

(D) 1, 2 and 3

Question #2

A Reversed Carnot Engine removes 50 kW from a heat sink. The temperature of the heat sink is 250 K and the temperature of the heat reservoir is 300 K. The power required by the engine is

(A) 10 kW

(B) 20 kW

(C) 30 kW

(D) 50 kW

Question #3

A heat engine receives heat at the rate of 2500 kJ/min and gives an output of 12.4 kW. Its thermal efficiency is, nearly:

(A) 18%

(B) 23%

(C) 26%

(D) 30%

Question #4

One reversible heat engine operates between 1000 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then the temperature T2 must be equal to:

(A) 582.7 K

(B) 632.5 K

(C) 682.8 K

(D) 732.5 K

Question #5

Consider the following statements for isothermal process:

1. Change in internal energy is zero

2. Heat transfer is zero

Which of the above statements is/are correct?

(A) 1 only

(B) 2 only

(C) Both 1 and 2

(D) Neither 1 nor 2

Question #6

A system of 100 kg mass undergoes a process in which its specific entropy increases from 0.3 kJ/kgK to 0.4 kJ/kgK. At the same time, the entropy of the surroundings decreases from 80 kJ/K to 75 kJ/K. The process is:

(A) Reversible and isothermal

(B) Irreversible

(C) Reversible only

(D) Isothermal only

Question #7

Which of the following statement is correct during adiabatic charging of an ideal gas into an empty cylinder from a supply main?

(A) The specific enthalpy of the gas in the supply main is equal to the specific enthalpy of the gas in the cylinder

(B) The specific enthalpy of the gas in the supply main is equal to the specific internal energy of the gas in the cylinder

(C) The specific internal energy of the gas in the supply main is equal to the specific enthalpy of the gas in the cylinder

(D) The specific internal energy of the gas in the supply main is equal to the specific internal energy of the gas in the cylinder

Question #8

Consider the following statements pertaining to Clapeyron equation:

1. It is useful in estimating properties like enthalpy from other measurable properties

2. At a change of phase, it can be used to find the latent heat at a given pressure

3. It is derived from the relationship
$\left ( \frac{\partial p}{\partial v} \right )_T=\left ( \frac{\partial s}{\partial T} \right )_v$

Which of the above statements are correct?

(A) 1 and 3 only

(B) 2 and 3 only

(C) 1 and 2 only

(D) 1, 2 and 3

Question #9

Consider the following conditions for the reversibility of a cycle:

1. The P and T of the working substance must not differ appreciably, from those of the surroundings at any state in the process

2. All the processes, taking place in the cycle, must be extremely slow

3. The working parts of the engine must be friction free

Which of the above conditions are correct?

(A) 1, 2 and 3

(B) 1 and 2 only

(C) 1 and 3 only

(D) 2 and 3 only