(b) 1° on the Kelvin scale
   (c) 1°on the Fahrenheit scale
   (d) 1°on the Reaumur scale
Ans: (b)
115. For shaving which type of mirror is used: [BPSC (Pre) 1999]
   (a) concave mirror
   (b) plane mirror
   (c) convex mirror
   (d) none of these
Ans: (a)
116. When a body moves with simple harmonic motion, then the phase
   difference between the velocity and the acceleration is - [NDA 2010]
   (a) 0°
   (b) 90°
   (c) 180°
   (d) 270°
Ans: (b)
117. An air bubble in water acts like a : [UPPCS (Pre) 2002]
   (a) convex mirror
   (b) convex lens
   (c) concave mirror
   (d) concave lens
Ans: (d)
118. A body is thrown vertically upwards and then falls back on the ground.
   Its potential energy is maximum - [NDA 2010]
   (a) on the ground
   (b) at the maximum height
   (c) during the return journey
   (d) both on the ground and at the maximum height
Ans: (b)
119. If the power of a convex lens is +2 diopter then the focal length of the
   lens is: [BPSC (Pre) 1996]