41. An investment is profitable if internal rate of return (IRR) is:

(a) Greater than the minimum rate of return fixed by the investor

(b) Less than the minimum rate of return fixed by the investor

(c) Equal to the minimum rate of return fixed by the investor

(d) Needed to be delinked from any prior stipulation of rate of return

Answer: (a)

42. A vertical photograph was taken at an altitude of 1200 m above the mean sea level (msl ). What is the scale of the photograph for terrain lying at elevation of 80 𝑚 and 300 𝑚 , if The focal length of the camera is 15 cm?

(a) 1:7467 and 1:6000

(b) 1:7985 and 1:6500

(c) 1:7467 and 1:6500

(d) 1:7985 and 1:6000

Answer: (a)

43. Fore bearing of a line AB is 12°24′. What would be its back bearing?

(a) 192°24′

(b) 167°36′

(c) 137°36′

(d) 102°24′

Answer: (a)

44. Prismatic compass measures directly:

(a) The reduced bearing

(b) The whole circle bearing

(c) Both reduced bearing and whole circle bearing

(d) Neither reduced bearing nor whole circle bearing

Answer: (b)

45. Mine dusts inhaled by workers produce a variety of Pneumokoniosis diseases. Of such dusts, which of the following minerals /metals/non-metals do not result in fibrosis?

(a) Asbestos, Iron oxide; Barytes

(b) Silica, Asbestos; Chromite

(c) Barytes, Kaolin, Chromite

(d) Silica, Iron ore, Barytes

Answer: (c)

46. The velocity of circulating air in a mine roadway can be measured by the:

1. Smoke-Cloud method

2. Tracer-Gas method

3. Hot-Wire method

Which of the above methods are applicable?

(a) 1 and 2 only

(b) 1 and 3 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (d)

47. One of the main problems / disadvantages associated with boundary ventilation system is:

(a) Reversal of air flow

(b) Variable volumetric efficiency

(c) Lower head requirement

(d) Isolation of section in an emergency

Answer: (a)

48. Which of the following materials are very effective when used as standard stone dust?

1. Shale

2. Dolomite

3. Gypsum

4. Limestone

(a) 1 and 2 only

(b) 2 and 3 only

(c) 3 and 4 only

(d) 1 and 4 only

Answer: (c)

49. A coal dust explosion will be classified as ‘strong’, based on the explosibility index, when the index is:

(a) 0.1 to 0.5

(b) 0.1 to 1

(c) 10 to 20

(d) 1 to 10

Answer: (d)

50. Which of the following chemicals the MSA detector tube contains, for testing the percentage of carbon monoxide gas?

(a) Silica gel + Palladium Sulphate

(b) Palladium Sulphate + Ammonium Molybdate

(c) Silica gel + Ammonium Molybdate

(d) Silica gel + Palladium Sulphate + Ammonium Molybdate

Answer: (d)