141. Particle nature of cathode rays is proved due to the fact that they ________________?

A. Travel in a straight line
B. Get deflected by magnetic electric field
C. Produce fluorescence
D. Heat the exposed material

142. Which of the following is prone to cup and cone fracture ?

A. Cast iron
B. Soft brass
C. Round specimen of ductile metal
D. Flat tensile specimen of ductile metal

143. Minimum safe distance between two liquid fuel storage tanks is equal to (where, H = height of the tank) ?

A. H
B. H/2
C. H/4
D. H/6

144. Austempering process results in the formation of ________________ structure ?

A. Martensitic
B. Bainitic
C. Carburised
D. Stressed

145. Good design of the casing of a centrifugal pump aims at minimising the __________________________?

A. Cavitation
B. Frictional losses
C. Kinetic energy loss
D. Static head

146. The ratio of mass of a neutron to that of an electron is about 1839. What is the ratio of the mass of a proton to that of an electron ?

A. 159
B. 1837
C. 2537
D. 10000

147. The rolling process cannot be used to produce______________________?

A. Plates
B. Rods
C. Tubes
D. Wires

148. In “Imperial Smelting Process” for extraction of zinc, zinc vapour thus produced is quenched in the external condenser by the use of the following _______________________?

A. Jet of water at high pressure
B. Blast of air
C. Mixture of water and air
D. Rain of molten lead

149. The most suitable material of construction for a sewer to carry sewage under high pressure is________________________?

A. Asbestos cement
B. Steel
C. Cement concrete
D. Stoneware

150. Which of the following is not a dielectric material ?

A. Cotton, silk and paper
B. Asbestos, glass, porcelain and mica
C. Rubber and polymeric resins
D. All refractory materials

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