JAMB - Physics (1979 - No. 30)
All the heat generated in a 5 ohms resistor by 2A flowing for 30 seconds is used to evaporate 5g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?
120J
60Jg-1
120Jg-1
1500J
1500Jg-1
Explicació
Heat energy = Electrical energy
mL = I2RT
5 x L = 2 x 2 x 5 x 30
L = 120Jg-1
mL = I2RT
5 x L = 2 x 2 x 5 x 30
L = 120Jg-1