Consider two hot bodies `B_(1)` and `B_(2)` which have temperature `100^(@)"C"` and `80^(@)"C"` respectively at t = 0. The temperature of surroundings is `40^(@)" C"`. The ratio of the respective rates of cooling `R_(1)` and `R_(2)` of these two bodies at` t = 0` will be

Options

A. `R_(1):R_(2)=3:2`
B. `R_(1):R_(2)=5:4`
C. `R_(1):R_(2)=2:3`
D. `R_(1):R_(2)=4:5`

Answer

A

Explanation

Initially at t = 0
Rate of cooling `(R ) prop` Fall in temperature of body `(theta-theta_(0))`
`rArr (R_(1))/(R_(2))=(theta_(1)-theta_(0))/(theta_(2)-theta_(0))=(100-40)/(80-40)=(3)/(2)`