51) When light enters from rare to denser medium, it bends towards the normal line, it is called
(A) Reflection of light
(B) Diffraction of light
(C) Refraction of light
(D) Absorption of light
52) Electromagnetic waves travel with the
(A) Speed of light
(B) Speed of sound
(C) Speed of earth rotation
(D) Speed of sun rotation
53) Sound travels faster in
(A) Dry air than in water
(B) Wood than in iron
(C) Iron than in air
(D) Hydrogen than in water
54) Soldiers crossing a suspension bridge, always break steps, in case the frequency of vibration of their marching should coincide with that of the bridge and this is because of the phenomenon of
(A) Refraction of sound
(B) Reverberation of sound
(C) Resonance of sound
(D) Echolocation of sound
55) On passing through foodstuff, x-ray can kill the
(A) Fungus
(B) Virus
(C) Bacteria
(D) Insects
56) Which of the following gives the correct descending order of elasticity in the substances?
(A) Rubber, silver, glass
(B) Silver, rubber, steel
(C) Steel, silver, rubber
(D) All have equal elasticity
57) Which of the following color of light travel through, glass with minimum speed?
(A) Red
(B) Violet
(C) Green
(D) Yellow
58) A Polaroid is
(A) A red light filter
(B) A device used for analyzing polarized light
(C) A device used in polarimeter
(D) An adjustable shutter
59) When a beam of light is passed through a transparent medium, however clear or homogeneous the medium may be, there is always a certain amount of light scattered sideways, out of the beam. This is known as
(A) Rayleigh scattering
(B) Dispersion
(C) Raman effect
(D) None of the above
60) The phenomenon of land and the sea breeze is as a result of
(A) Conduction
(B) Convection
(C) Radiation
(D) None of these