Ans: (b)
452. "Every action has an equal and opposite reaction" is Newton"s law of
   (a) first
   (b) second
   (c) third
   (d) fourth
Ans: (c)
453. Which force is used when milk is churned to separate cream?
   (a) cohesive
   (b) centrifugal
   (c) frictional
   (d) gravitational
Ans: (b)
454. The colour or an opaque object is due to the colour it
   (a) absorbs
   (b) refracts
   (c) reflects
   (d) scatters
Ans: (c)
455. The focal length or lens or the eye is under the control or the
   (a) iris
   (b) pupil
   (c) ciliary body
   (d) cornea
Ans: (c)
456. In the ramous equation of Einstein E = mc2 , "c" denotes.
   (a) velocity of sound
   (b) velocity of light
   (c) a constant factor
   (d) wavelength of light
Ans: (b)