Answer to Question #155169 in Electric Circuits for Aoife

Question

Describe how the equipment can be used to find the power of another battery charger.

The equipment is: power supply, clock, battery charger, joulemeter and battery,

Answer 1

Power is how quickly a work can be done. Since the work is done by consuming certain energy, the work and energy are equivalent concepts in the context of this experiment. So, the power is

$$P=\frac{E}{t}$$

To find the power of a charger, divide energy passed thru the charger by the time it took to charge an empty battery.

1) Make sure the battery is depleted

2) Connect the charger to the joulemeter to measure energy

3) Connect the charger to the battery and start your stopwatch

4) As the battery is charged, stop the stopwatch, record the time

5) Look at the joulemeter and record the value of energy

6) Divide the energy by the time according to the equation