# Mechanical Engineering Thermodynamics – Set 13

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## Q1. The heat and mechanical energies are mutually convertible. This statement was established by

(A) Boyle
(B) Charles
(C) Joule
(D) None of these

(A) 0
(B) 1
(C) γ
(D) ∝

## Q3. When the gas is heated at constant pressure, the heat supplied

(A) Increases the internal energy of the gas
(B) Increases the temperature of the gas
(C) Does some external work during expansion
(D) Both (B) and (C)

Answer: (D) Both (B) and (C)

## Q4. First law of thermodynamics deals with

(A) Conservation of heat
(B) Conservation of momentum
(C) Conservation of mass
(D) Conservation of energy

(A) 1
(B) 0
(C) -1
(D) 10

(A) Oxygen
(B) Nitrogen
(C) Hydrogen
(D) Methane

## Q7. A cycle consisting of two constant pressure and two isentropic processes is known as

(A) Carnot cycle
(B) Stirling cycle
(C) Otto cycle
(D) None of these

## Q8. Which of the following is correct?

(A) Absolute pressure = Gauge pressure + Atmospheric pressure
(B) Gauge pressure = Absolute pressure + Atmospheric pressure
(C) Atmospheric pressure = Absolute pressure + Gauge pressure
(D) Absolute pressure = Gauge pressure – Atmospheric pressure

Answer: (A) Absolute pressure = Gauge pressure + Atmospheric pressure

(A) √(KT/m)
(B) √(2KT/m)
(C) √(3KT/m)
(D) √(5KT/m)

## Q10. When the gas is cooled at constant pressure,

(A) Its temperature increases but volume decreases
(B) Its volume increases but temperature decreases
(C) Both temperature and volume increases
(D) Both temperature and volume decreases

Answer: (D) Both temperature and volume decreases

## Q11. The principal constituents of a fuel are

(A) Carbon and hydrogen
(B) Oxygen and hydrogen
(C) Sulphur and oxygen
(D) Sulphur and hydrogen

## Q12. Kelvin-Planck’s law deals with

(A) Conservation of work
(B) Conservation of heat
(C) Conversion of heat into work
(D) Conversion of work into heat

Answer: (C) Conversion of heat into work

## Q13. The efficiency of Diesel cycle approaches to Otto cycle efficiency when

(A) Cut-off is increased
(B) Cut-off is decreased
(C) Cut-off is zero
(D) Cut-off is constant

(A) Zero
(B) 1/5
(C) 4/5
(D) 1

## Q15. The change of entropy, when heat is absorbed by the gas, is

(A) Positive
(B) Negative
(C) Positive or negative
(D) None of these

(A) Zeroth
(B) First
(C) Second
(D) Third

## Q17. One kilowatt is equal to

(A) 1 N-m/s
(B) 100 N-m
(C) 1000 N-m/s
(D) 1 × 106 N-m/s

## Q18. When a gas is heated at constant volume

(A) Its temperature will increase
(B) Its pressure will increase
(C) Both temperature and pressure will increase
(D) Neither temperature nor pressure will increase

Answer: (C) Both temperature and pressure will increase

(A) 1
(B) 1.4
(C) 1.45
(D) 2.3