Extremely simple question for you. Probably beneath all of you to answer apologies for that. My camera's flash is rated in Watt seconds. My battery is rated in mAh .

If my battery can output 1000 milliamp hours and outputs at 110 Volts. And my camera flash draws 100 Watt seconds per fire. Assuming there are no other variables and it's a perfect system, how many camera flashes could I fire.

## Best Answer

$$1000\mathrm{\ mA \cdot h}\times110\mathrm{\ V} = 396\mathrm{\ kJ}$$

$$100\frac{\mathrm{\ W \cdot s}}{\text{flash}} = 100\frac{\mathrm{\ J}}{\text{flash}}$$

$$\frac{396\mathrm{\ kJ}}{100\frac{\mathrm{\ J}}{\text{flash}}} = 3960\text{ flashes}$$