A heater marked 50W will evaporate 0.005kg of boiling water in 50 seconds. The specific latent heat of vaporization of water in J/kg is
-
A.
5.0 x 106 -
B.
1.0 x 106 -
C.
2.5 x 106 -
D.
2.5 x 105 -
E.
5.0 x 105
Correct Answer: Option E
Explanation
Heat energy = Electrical energy
mL = power x time
0.005 x L = 50 x 50
L = 5 x 105J/kg