# (Detailed solution) IES 2017 | Thermodynamics Questions

## IES 2017 Thermodynamics Questions

Question #1

During a constant pressure expansion of a gas, 33.3% heat is converted into work while the temperature rises by 20K. The specific heat of the gas at constant pressure as a proportion of work, W is

(A) 8%

(B) 10%

(C) 12%

(D) 15%

Question #2

A cylinder contains 10 m3 of an ideal gas at a pressure of 2 bar. This gas is compressed in a reversible isothermal process till its
pressure increases to 15 bar. What quantum of work will be required for this process? (You can use the table given herewith.)

 Number 2 2.5 3 5 7 Log10 0.301 0.397 0.475 0.698 0.845

(A) 4500 kJ

(B) 4030 kJ

(C) 450 kJ

(D) 403 kJ

Question #3

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

(A) reversible and isothermal

(B) irreversible

(C) reversible only

(D) isothermal only

Question #4

reversible heat engine rejects 80% of the heat supplied during a cycle of operation. If the engine is reversed and operates as a refrigerator, then its coefficient of performance shall be

(A) 6

(B) 5

(C) 4

(D) 3

Question #5

The thermal efficiency of the hypothetical cycle shown is

(A) 0.6

(B) 0.5

(C) 0.4

(D) 0.3

Question #6

A heat engine working on the Carnot cycle receives heat at the rate of 50 kW from a source at 1300K and rejects it to a sink at 400K. The heat rejected is
(A) 20.3 kW

(B) 15.4 kW

(C) 12.4 kW

(D) 10.8 kW

Question #7

An ideal gas is flowing through an insulated pipe at the rate of 3.3 kg. There is a pressure drop of 15% from the inlet to the outlet of
the pipe. What is the rate of energy loss because of this pressure drop due to friction, given that Rgas=0.287 kJ/kg K and the
reference temperature T0 is 300K?

(A) 42.62 kW

(B) 40.26 kW

(C) 38.14 kW

(D) 35.13 kW

Question #8

For a steady process, the conditions at stage 1 and stage 2 are, respectively, h1=300 kJ/kg, h2=150 kJ/kg, S1=1.25 kJ/kg K and
S2=0.8 kJ/kg K. The ‘availability’ at the ambient temperature 300K will be

(A) 15 kJ

(B) 20 kJ

(C) 25 kJ

(D) 35 kJ

Question #9

Volumetric analysis of a certain flue gas gave CO2 15%, O2 5% and rest as N2. The gas was at a temperature of 200°C and a pressure of 5 bar. The partial pressure of N2 in the flue gas is

(A) 250 kN/m2

(B) 300 kN/m2

(C) 350 kN/m2

(D) 400 kN/m2