51. How much heat will be evolved when 2.7𝑔 of aluminium reacts with stoichiometric amount of Fe2O3?
(a) −42.6 kJ
(b) −4.26 kJ
(c) 4.26 kJ
(d) 42.6 kJ

Answer: (a)

52. Fins are used in heat transfer equipment to:
(a) Increase heat transfer area
(b) Decrease heat transfer area
(c) Decrease mechanical strength
(d) Support the heating system

Answer: (a)

53. Which of the following mixtures forms an azeotrope at atmospheric pressure?
1. Water-alcohol
2. Methyl alcohol-acetone
3. Benzene-Toluene
4. Butyl acetate-water

(a) 1, 2 and 3
(b) 1, 3 and 4
(c) 1, 2 and 4
(d) 2, 3 and 4

Answer: (c)

54. The heat in a unit of time produced when a steady state current I passes through an electrical conductor having resistance R is

Answer: (b)

55. Lewis number is the ratio of
(a) Thermal diffusivity to mass diffusivity
(b) Mass diffusivity to thermal diffusivity
(c) Mass diffusivity to momentum diffusivity
(d) Momentum diffusivity to thermal diffusivity

Answer: (a)

56. Which one of the following is the dynamic characteristic of an instrument?
(a) Reproducibility
(b) Sensitivity
(c) Dead zone
(d) Fidelity

Answer: (d)

57. When the power necessary to alter the controlled output is supplied primarily from sources other than the command input the feedback control system is called
(a) Active
(b) Positive
(c) Hybrid
(d) Passive

Answer: (a)

58. In Aircraft, redundant sensors are used for
1. Controlling the speed
2. Controlling the flow of fuel
3. Reliability

(a) 1 only
(b) 2 only
(c) 3 only
(d) 1, 2 and 3

Answer: (c)

59. Efficiency of Carnot’s engine is 100 %, when
(a) Sink is placed at 0° 𝐶
(b) Sink is placed at 0 𝐾
(c) Source is placed at 100° 𝐶
(d) Source is placed at 100 𝐾

Answer: (b)

60. 

Answer: (d)