(d) Yukawa
Ans: (a)
179. Microwave oven consumes less power due to: [NDA,2010]
   (a) small frequency of radiation
   (b) short wavelength of radiation
   (c) large frequency as well as wavelength of radiation
   (d) small frequency as well as wavelength of radiation
Ans: (a)
180. The sun is constantly radiating energy and yet is surface temperature is
   nearly constant at 6000°C.The constancy of solar temperature is due to:
   [NDA 2010]
   (a) fission
   (b) black hole evaporation
   (c) fusion
   (d) radioactivity
Ans: (c)
181. Metal pipes used to carry water sometimes burst in the winter. This is
   because: [NDA 2010]
   (a) water expands when it freezes
   (b) metal contracts more than water
   (c) outside of the pipe contracts more than inside
   (d) metal expands more than water
Ans: (a)
182. The mesons are:
   (a) positively charged particles
   (b) negatively charged particles
   (c) neutral
   (d) All of these
Ans: (d)
183. If three identical resistors each of resistance r are connected in parallel,
   then the equivalent resistance of the three resistors will be : [NDA 2010]
   (a) 3/r