The initial temperature of a body is 80 oC. Its temperature falls to 64 oC in 5 minutes and to 52 oC in next 10 minutes. If the temperature of surrounding is 7n oC, value of n is
According to Newton’s law:θ1−θ2t = k[θ1+θ22−θ0]
⇒ 3.2 = K[72−θ0]
⇒ 1.2 =K[58−θ0]
On solving above two equations, we get θ0=49 oC.
Hence, n = 7.