Water is being boiled in a flat bottomed kettle placed on a stove. The area of the bottom is `300cm^(2)` and the thickness is `2mm`. If the amount of steam produced is `1gm min^(-1)`, then the difference of the temperature between the inner and the outer surface of the bottom is (thermal conductivity of the material of the kettle `0.5calcm^(-1)s^(-1)C^(-1)`, latent heat of the steam is equal to `540calg^(-1))` .

Options

A. `12^(@)C`
B. `1.2^(@)C`
C. `0.2^(@)C`
D. `0.012^(@)C`

Answer

D

Explanation

`(dtheta)/(dt) = L.(dm)/(dt)` = Heat transfer from bottom = `(TD)/(l//KA)`
Heat TD = desired temperature difference
`therefore` `(L.l.(dm)/(dt))/(KA) = ((540)(2 xx 10^(-1)(1/60)))/(0.5 xx 300)=0.012^(@)`C