Time Left - 12:00 mins

BARC 2020: Thermo Nuclear Quiz 2

Attempt now to get your rank among 713 students!

Question 1

Two rigid tanks, each filled with 50 kg of air, have temperature of 900 K and 400 K. A heat engine placed between the two tanks extracts heat from the high temperature tank, produces work, and rejects heat to the low temperature tank. Maximum work obtained from the tank is ________ kJ.

Question 2

A piston – cylinder device contains helium gas initially at 150 kPa, 20, and 0.5 m3. The helium is now compressed in a polytropic process to 400 kPa and 140. Determine the heat loss or gain during the process.
RHe = 2.0769 kJ/kgK; Cv = 3.1156 kJ/kgK.

Question 3

Air enters an insulated diffuser operating at steady state with a pressure of 0.65 bar, temperature of 67 and a velocity of 300 m/s. The inlet area is 0.5 m2. At the exit, the pressure is 1 bar and the area is 0.6 m2. Potential energy changes can be neglected. Assume ideal gas behavior for air. The mass flow rate and temperature of the air at exit is

Question 4

Find the increase in unavailable energy associated with transfer of 800kJ of heat from a constant temperature system at 600K to another constant temperature at 400K. The ambient temperature is 300K.

Question 5

5 kg of water at 27 °C is mixed with 10 kg of water at 97 °C in a steady flow process. If room temperature is 27 °C then the unavailable energy with respect to the water at 27 °C is

Question 6

Which of the following is true for a pure substance at critical point _________.

Question 7

A 75 ohm resistor carrying a constant current of 1 A is kept at a constant temperature of 27 °C by a stream of cooling water. In a time interval of 1s. What is the change in entropy of the universe?

Question 8

5 kg of a perfect gas whose temperature varies from 137 °C to 230 °C during a constant volume process. The specific heat varies linearly with absolute temperature and is represented by the relation: cv = (0.46 + 0.0098 T) kJ/kg K. Evaluate the entropy change.

Question 9

10 kg of ice at –13 °C is exposed to the atmosphere which is at 23 °C. The ice melts and comes into thermal equilibrium. Total entropy change of ice as it comes to thermal equilibrium with the environment is _____ kJ.

Cp of ice = 2.093 kJ/kg°C, Latent heat of fusion of ice = 333.33 kJ/kg.

Question 10

During the quenching process, a hot iron of mass 25kg and at a temperature of 450oC is dropped in 180kg of oil at 20oC and having specific heat of 2.5 KJ/KgK. Assume specific heat of hot iron as 0.5 KJ/KgK .The entropy change (in KJ/K) of oil is
  • 713 attempts