(b) Plane meter
   (c) Altimeter
   (d) Hydrometer
Ans: (c)
229. The device through which the intensity of the sunrays is measured: [RRB
   GG 2003]
   (a) Astrometer
   (b) Chrescograph
   (c) Barometer
   (d) Actiometer
Ans: (d)
230. Solar radiation is measured by :
   (a) Pyrometer
   (b) Astrometer
   (c) Barometer
   (d) Manometer
Ans: (a)
231. The device through which the depth of the sea is measured by the use of
   sound wave: [SSC Grad 2003]
   (a) Radar
   (b) Sonar
   (c) Altimeter
   (d) Venturimeter
Ans: (b)
232. The use of thermostat is : [MPPCS (Pre) 2004]
   (a) to measure temperature
   (b) to increase temperature
   (c) to keep constant temperature
   (d) to convert temperature into electricity
Ans: (c)
233. The radiator of vehicles are used for:
   (a) to heat the engine