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 ▸

Explain the difference between current and voltage


What is the difference between nuclear fusion and fission?


Using the principle of the conservation of energy, calculate the maximum speed of a ball of 5.0kg that has been dropped from a height of 20m. (Given that the gravitational field strength is equal to 9.8N/kg)


Explain why an ice cube submerged in a drink melts faster than an ice cube on a kitchen surface (the drink, surface and room temperature are all equal). (3 marks)