Question

One end of a copper rod of length 1 m and area of cross - section `400 xx (10^-4) m^2` is maintained at `100^@C`. At the other end of the rod ice is kept at `0^@C`. Neglecting the loss of heat from the surrounding, find the mass of ice melted in 1h. Given, `K_(Cu) = 401 W//m-K and L_f = 3.35 xx (10^5) J//kg.`

Answer 1

Correct Answer - A::B
Thermal resistance of the rod

`R = l/(KA) = (1.0)/((401)(4xx (10^-4))) = 6.23 K//W`
`:.` Heat current , `H = ("Temperature difference")/("Thermal resistance")`
`= ((100-0)/6.23) = 16W`
Heat transferred in 1 h,
`Q = Ht (:. H = Q/t)`
`= (16)(3600) = 57600J`
Now, let m mass of ice melts in 1 h, then
`m=Q/L`
`= 57600/(3.35 xx (10^5))`
` =0.172`
or `=172 g` .