A body cools down from `50^(@)C` to `45^(@)C` in 5 minutes and to `40^(@)C` in another 8 minutes. Find the temperature of the surrounding.

Answer

C, D

Explanation

`V = 100CC, Deltatheta = 5^(0) C, T = 5 min`
for water
`(msDeltatheta)/(dt) = (KA)/l`
for kerosene
`(ms)/(dt) = (KA)/(l) 1/(Deltatheta)`
`implies (100 xx 10^(-3) xx 800 xx 2100)/(t)`
`= (100 xx 10^(-3) xx 1000 xx 4200)/(5)`
`implies t = (5 xx 800 xx 2100)/(1000 xx 4200) = (2000)/(1000)`