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 ▸

How many times further away from the pivot point of a seesaw does someone of double the weight have to sit in order for the it to balance?


Why are some electromagnetic waves harmful to humans?


Explain in terms of specific heat capacity why a hot water bottle is good at heating a bed.


What is the difference between reflection, refraction and diffraction?