PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity
Problem
A 40W lamp is left on for 4h, while a 60W lamp is left on for 2h. Which statement correctly compares the electrical energy each lamp converts during the time it is on?
(a) The 60W lamp converts more energy because its power rating is higher, even though it is on for less time.
(b) Both lamps convert the same amount of energy because the product Pt is the same for each.
(c) The 40W lamp converts more energy because it is on for a longer time.
(d) Both lamps convert the same amount of energy because electrical energy depends only on the supply voltage, not on how long the device operates.