41. Consider the following statements regarding petroleum:
1. It is the only liquid fuel in nature
2. Its various fractions are separated by fractional distillation
3. Its approximate composition is 𝐶=84%, 𝐻=15%, 𝑁+𝑆+𝑂=1%
4. It has higher thermal efficiency than diesel

Which of the above statements are correct?
(a) 1, 2 and 3
(b) 1, 2 and 4
(c) 1, 3 and 4
(d) 2, 3 and 4

Answer: (a)

42. Paraffins are desirable in lubricating oil as it has high
(a) Viscosity index
(b) Pour point
(c) Smoke point
(d) Octane number

Answer: (a)

43. Age of crude oil is indicated by:
1. Universal oil products factor
2. Carbon Preference Index

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (b)

44. At what temperature is the extraction of liquid sulphur dioxide carried out from kerosene in order to improve the illuminating quality of kerosene?
(a) 14° 𝐶
(b) 4° 𝐶
(c) −4° 𝐶
(d) −14° 𝐶

Answer: (d)

45. Dittus-Boelter equation used for predicting the tube-side heat transfer coefficient is in the range of:
(a) Reynolds number 𝑅 ≤4000
(b) Reynolds number 𝑅 ≤8000
(c) Reynolds number 𝑅 >10,000
(d) Reynolds number 𝑅 >5,000

Answer: (c)

46. LMTD correction factor is used in the design of a shell and tube heat exchanger, to account for:
1. Mixed flow cases
2. Viscosity variations of the working fluids due to temperature change
3. The presence of baffles

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

Answer: (a)

47. Which one of the following number is a measure to determine the relative strength of conduction and convection?
(a) Rayleigh number
(b) Reynolds number
(c) Peclet number
(d) Sherwood number

Answer: (a)

48. When heat transfer takes place through a series of flat plates, the overall resistance is the
(a) Logarithmic mean of resistances
(b) Average of resistances
(c) Geometric mean of resistances
(d) Sum of the resistances

Answer: (d)

49. Which one of the following statements is correct?
(a) Both Peltier and Joule effects are reversible
(b) Both Peltier and Joule effects are irreversible
(c) Joule effect is reversible whereas Peltier effect is irreversible
(d) Joule effect is irreversible whereas Peltier effect is reversible

Answer: (d)

50. Which one of the following medium is required for the transfer of heat by electromagnetic waves or photons?
(a) Solid
(b) Liquid
(c) No medium
(d) Gases

Answer: (c)