The temperature of a body falls from 40 ° C to 36 ° C in 4 minutes , when placed in a constant ambient temperature of 20 ° C . The time it takes for the temperature to fall from 36 ° C to 32 ° C in the same ambient temperature is

Step-by-step solution

Let θ be instantaneous temperature, θ For 40 ° C → 36 ° C 36 - 40 4 = - k ( 38 - 20 ) . . . ( i ) θ a v g = 38 ° C For 36 ° C → 32 ° C 32 - 36 t = - k ( 34 - 20 ) . . . ( ii ) θ a v g = 34 ° C ( i ) ( ii ) Gives t = 4 18 14 ⇒ t = 5 . 1 min