149. When water is heated from 0°C to 10°C the volume of water: [CBI 1991]
       (a) increases steadily
       (b) decreases steadily
       (c) first increases then decreases
       (d) first decreases then increases
Ans : (d)
150. How should a man wearing spectacles work with a microscope? [RRB 1993]
       (a) He should keep on wearing spectacles
       (b) He should take off spectacles
       (c) He cannot use the microscope at all
       (d) Wearing or taking off makes little difference
Ans : (a)
151. The weight "of an object would be minimum when it is placed: [CDS 1992]
       (a) at the equator
       (b) at the North Pole
       (c) at the South Pole
       (d) at the centre of the earth
Ans : (d)
152. When an open bottle of scent is kept in a corner of the room, its odour is felt in all the corners, This is due to the phenomenon of:
       (a) vaporisation
       (b) evaporation
       (c) diffusion
       (d) sublimation
Ans : (c)
153. Speed of sound is greater in solids than in liquids because: [IFS 1989]
       (a) the atoms in solids are regularly arranged
       (b) the atoms in liquids are loosely packed
       (c) the solids have high elasticity
       (d) None of the above
Ans : (c)
154. Which of the following are phenomenon exhibited by sound waves? [NDA 1992]
                1) Reflection
                2) Refraction
                3) Interference
                4) Polarisation
                5) Diffraction
       (a) 1, 2, 3
       (b) 1, 2, 3, 5
       (c) 1, 3, 4, 5
       (d) 2, 3, 4, 5
Ans : (b)
155. Match the following: [NDA 1990]
           Parameters                       Dependence
     A.   lntensity of light          1.   Properties of the