(b) to prevent thermal radiation
   (c) to keep cool the engine
   (d) None of these
Ans: (c)
234. The device to record and to reproduce the detection of the recording is
   called: [RRB ASM/GG 2004]
   (a) Audio phone
   (b) Detectophone
   (c) Gramophone
   (d) Microphone
Ans: (c)
235. The law of floatation was invented by : [RRB Disel Assit. 2002]
   (a) Newton
   (b) Wright Brothers
   (c) Galileo
   (d) Archemedes
Ans: (d)
236. ln isobaric and isochoric thermo dynamical processes:
   (a) pressure and volume remain constant
   (b) volume and pressure remain constant
   (c) pressure and temperature remain constant
   (d) None of these
Ans: (a)
237. ln the adiabatic process, which one of the following remains constant:
   (a) heat
   (b) entropy
   (c) Both of these
   (d) None of these
Ans: (c)
238. ln the ideal gas which type of energy is absent:
   (a) Kinetic energy
   (b) Potential energy