81. In which one of the following molecules, a bond having significant non-bonding ionic quality exists?

(a) Hypervalent molecules
(b) Multivalent molecules
(c) Divalent molecules
(d) Monovalent molecules

Answer: (a)

82. Which one of the following constituents of cement possesses least setting time?

Answer: (a)

83. Bernoulli’s equation for fluid flow describes
(a) Kinetic energy balance in laminar flow
(b) Mechanical energy balance in potential flow
(c) Mechanical energy balance in turbulent flow
(d) Kinetic energy balance in boundary layer

Answer: (b)

84. Which one of the following pumps can be used for pumping slurry?
(a) Centrifugal
(b) Diaphragm
(c) Reciprocating
(d) Pneumatic

Answer: (b)

85. The working principle of the radiation pyrometer is based on
(a) Wien’s law
(b) Kirchhoff’s law
(c) Stefan-Boltzmann law
(d) Seebeck effect

Answer: (c)

86. Which one of the following pumps can be used for the recirculation of molten sodium coolant in liquid metal cooled reactor?
(a) Electromagnetic
(b) Reciprocating
(c) Centrifugal
(d) Volute

Answer: (a)

87. How much enrichment of  is required in a fast breeder reactor nuclear fuel?
(a) 0 %
(b) 25 %
(c) 50 %
(d) 100 %

Answer: (a)

88. The graphite rod in the nuclear pile
(a) Converts fast moving neutrons into thermal neutrons
(b) Reacts with  to release energy
(c) Furnishes deuterons to fission 
(d) Undergoes combustion which triggers the fission reactions

Answer: (a)

89. Which of the following are responsible for the bulk of the long-term radioactivity?
(a) U, Pu and Cm
(b) Ac, Th and Cf
(c) U, Pu and Ra
(d) U, Th and Pu

Answer: (a)

90. Which one of the following statement is correct?
(a) Positron is the antiparticle of electron
(b) In 𝛼-decay, the ratio of neutron to proton decreases
(c) Ionizing power of 𝛽-rays is higher than that of 𝛼-rays
(d) Speed of 𝛼-rays is more than that of 𝛾-rays

Answer: (a)