Question

D) 0.2
85) A piece of ice (heat capacity = 2100 Jkg.' °C and
latent heat = 3.36 x 105 J/kg) of mass m grams is at -5 °C
at atmospheric pressure. It is given 420 J of heat so that
the ice starts melting. Finally when the ice-water mixture
is in equilibrium, it is found that 1 g of ice has melted.
Assuming there is no other heat exchange in the process,
the value of mis
A) 10
B) 4
C) 8
D) 6
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Answer 1

Hence the value pf m is 8 g.

Option (C) is correct.

Explanation:

Given data:

S(ice) =  2100 J Kg

Latent heat = 3.36 x 105 J/kg

Q = 420 J

Q1 = - 5°C

M (ice ) = 1 g = 10^-3 Kg

Let M Kg ice be originally present.

We know that

m x S (ice)  [ 0 -  θ1 ] + M (ice ) x L = Q

m x 2100 [ 0 - (-5)] + 1/ 1000 x 3.36 x 10^5 = 420

m x 2100 x 5 = 420 - 336

m = 420 - 336 / 2100 x 5

m = 8 g

Hence the value pf m is 8 g.