437. Velocity of sound in high altitudes is low because at such a height
   (a) the temperature is low
   (b) there is no air
   (c) the pressure is low
   (d) All the above
Ans: (a)
438. A boy sitting in a train moving with a uniform velocity drops a coin
   outside. A man standing outside the train will find the trajectory of the coin
   to be
   (a) a parabola
   (b) a horizontal straight line
   (c) a vertical straight line
   (d) a circle
Ans: (a)
439. Raindrops assume a spherical shape because or
   (a) adhesion
   (b) surface tension
   (c) gravitational force
   (d) atmospheric pressure from all sides
Ans: (b)
440. Which mirror is used as a rear view mirror in Vehicles?
   (a) Parabolic
   (b) Convex
   (c) Concave
   (d) Plain
Ans: (b)
441. Acoustics is a property or
   (a) Physics
   (b) Chemistry
   (c) Biology
   (d) Economic
Ans: (a)