Q.

The temperature of a body in air falls from 40°C to 24°C in 4 minute. The temperature of the air is 16°C. The temperature of the body in the next 4 minutes will be          [2025]

1 14/3°C  
2 28/3°C  
3 56/3°C  
4 42/3°C  

Ans.

(3)

T2T1t=K[TavgTs]

        T1=24°C; T2=40°C; t=4, Ts=16°C

40244=K[3216]

          K=416=14

Now 24T4=K[T+24216]

          24T=T82

            3T2=28  T=563°C