The minimum temperature of air in the reservoir should be

Question

Air from a reservoir is to be passed through a supersonic nozzle so that the jet will have a Mach number of 2. If the static temperature of the jet is not to be less than 27⁰C, the minimum temperature of air in the reservoir should be 

(a) 48.6⁰C                    (b) 167⁰C

(c) 276⁰C                     (d) 367⁰C