A calorimeter of mass `0.2 kg` and specific heat `900 J//kg-K`. Containing `0.5 kg` of a liquid of specific heat `2400 J//kg-K`. Its temperature falls from `60^(@)C` to `55^(@)C` in one minute. Find the rate of cooling.

Options

A. `5 J//s`
B. `15 J//s`
C. `100 J//s`
D. `115 J//s`

Answer

D

Explanation

Rate of cooling (here it is rate of loss of heat)
`(dQ)/(dt) = (mc+W) (d theta)/(dt)=(m_(1)c_(1)+m_(c)c_(c))(d theta)/(dt)`
`rArr (dQ)/(dt) = (0.5xx2400+0.2xx900)((60-55)/(60))`
`115 (J)/(sec)`.