A 10 \Omega coil takes 21 s to melt 10g of ice at 0ºC. Assuming no heat losses, determine the current in the coil. (Specific latent heat of fusion of ice = 336 Jg\(^{-1}\))
A
16A
B
5A
C
4A
D
3A
Verified Correct Answer: C.
Physical Principles & Numerical Solution
Heat lost = Heat used to melt ice
I\(^2\)R t = mL
I\(^2\) x 10 x 21 = 10 x 336
I\(^2\) = \(\frac{3360}{210}\) = 16
I = \(\sqrt{16}\) = 4A.
Source: Myschool Past Questions Archive (Record #25505)