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
Verified Correct Answer: E.
Physical Principles & Numerical Solution
Heat energy = Electrical energy
mL = power x time
0.005 x L = 50 x 50
L = 5 x 105J/kg
Source: Myschool Past Questions Archive (Record #28929)