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 crash tested. Car A has a crumple zone, B doesn't. Both cars have mass 1500kg and a driver of mass 80kg and crash at 20m/s. Cars A and B take 0.8 and 0.2 seconds to stop respectively. Using this information, are crumple zones a necessity? (6)
Which state can a substance NOT be in if heat transfer through convection is occurring?
A Car of mass 1000kg applies a constant 200N breaking force over a distance of 30m and comes to a complete stop. How fast was the car going the instant the brakes were engaged.
A kettle is found to output 65J when its input energy is 100J. What is the efficiency of the kettle, and what happens to the rest of the energy?