276. To operate through any laser it is common to achieve:
   (a) population inversion
   (b) a meta excited state
   (c) a super excited state
   (d) None of these
Ans: (c)
277. Which one of the following is marked on the common use fluorescent
   (a) 220K
   (b) 273K
   (c) 6500K
   (d) 9000K
Ans: (c)
278. Which of the following is the mathematical statement of second law of
   (a) dQ = Tds
   (b) dS = TdQ
   (c) TdU = dQ
   (d) None of these
Ans: (a)
279. The ratio of the specific heat capacities of a diatomic gas is :
   (a) 1.33
   (b) 1.44
   (c) 1.66
   (d) None of these
Ans: (b)