A 6.0W bulb is connected to a source of 480J of energy. Assuming the system is 100% efficient, and the bulb runs at full power, how long can it stay lit?

  • Bulb power = 6.0W - Energy provided = 480J - Use equation P = E / t (Power = energy/time) where power is in watts, energy is in joules, and time is in seconds - Rearrange the equation to give t = E / P (time = energy/power) to find the time in seconds - Plug in the values to give t = 480/6 = 80 - Therefore time = 80 seconds.
LW

Related Physics GCSE answers

All answers ▸

Two cars are moving parallel to each other on a road. The first car is moving at a speed of 11 m/s, while the second car is moving at 17 m/s, what is the speed of the second car, relative to the first car.


A car driver has to make an emergency stop. The braking distance depends on the speed of the car. For the same braking force, what happens to the braking distance if the speed doubles?


Suppose a student wants calculate the density of the two different objects, a metal cube and a small statue. Describe the methods the student could use to measure the density of the two objects.


What is the law of conservation of energy?