Question

The ice is filled in a hollow glass sphere of thickness `2mm` and external radius `10cm`. This hollow glass sphere with ice now placed in a bath containing boiling water at `100^(@)C`. Calculate the rate at which ice melts. Neglect volume change in ice.
(Given, thermal conductivity of glas `1.1W//m//K`, latent heat of ice `=336xx10^(3)J//kg)`
A. `m/t=0.01kg//s`
B. `m/t=0.002kg//s`
C. `m/t=0.02kg//s`
D. `m/t=0.001kg//s`

Answer 1

(c) Rate of transmission of heat `(dQ)/(dt)=(4piKr_(1)r_(2)Delta theta)/((r_(2)-r_(1)))`
`:.(dQ)/(dt)=(4xxpixx1.1xx0.098xx0.1xx100)/(0.002)=6769.8~~6770W`
Rate of ice melt `=m/timplies(m/t)L=(d theta)/(dt)`
`(m/t)xx336xx10^(3)=6770impliesm/t=0.02kg//s`