JAMB - Physics (1997 - No. 20)
A heating coil rated at 100W is used to boil off 0.5kg of boiling water. The time taken to boil off the water is [specific latent heat of vaporization of water = 2.3 x 106Jkg-1]
1.15 x 109 s
1.15 x 107 s
1.15 x 105 s
1.15 x 104 s
Vysvětlení
Heat energy = Elect. energy
0.5 x 2.3 x 106 = 100t
t = 1.15 x 104s
0.5 x 2.3 x 106 = 100t
t = 1.15 x 104s