Physics
Physics
Problem
A lamp is kept ON for 30 minutes on one day and for 2 hours on the next day. Neglecting any other changes, the electrical energy consumed on the second day is __________ the energy consumed on the first day. a) twice b) four times c) one-fourth of d) the same asIntuitive explanation
The key here is that energy consumption depends on both power and time—specifically, . Since the lamp is identical both days, its power stays constant. The only thing changing is how long it runs: 30 minutes versus 2 hours. Compare the time intervals as a ratio to find how many times more energy is used on day two.
Intuitive explanation
The key here is that energy consumption depends on both power and time—specifically, . Since the lamp is identical both days, its power stays constant. The only thing changing is how long it runs: 30 minutes versus 2 hours. Compare the time intervals as a ratio to find how many times more energy is used on day two.