(a) 200 cm
   (b) 100cm
   (c) 50 cm
   (d) 2 cm
Ans: (c)
120. The colour of an opaque object is due to that colour which: [IAS (Pre)
   (a) is absorbed
   (b) is not reflected
   (c) is reflected
   (d) is scattered
Ans: (b)
121. Which one of the following pairs does not have the same dimension
   [NDA 2010]
   (a) Potential energy and kinetic energy
   (b) Density and specific gravity
   (c) Focal length and height
   (d) Gravitational force and frictional force
Ans: (b)
122. The best and the poorest conductors of heat are respectively? [NDA
   (a) silver (Ag) and lead (Pb)
   (b) Copper(Cu) and aluminium (AI)
   (c) silver (Ag) and gold (Au)
   (d) copper (Cu) and gold (Au)
Ans: (a)
123. The three fundamental colours are: [MPPCS (Pre) 2004, RRB TC 2005]
   (a) blue, yellow and red
   (b) blue, green and red
   (c) yellow, green and red
   (d) blue, yellow and green
Ans: (b)