Aclothes dryer uses about 8 amps of current from a 240 volt line. how much power does it use?

Power = 1920 watt

Explanation:
The equation that relates power, voltage and current is:
P = V * I
where:
P is the power we want to calculate
V is the voltage = 240 volt
I is the current = 8 ampere

Substitute with the givens in the above equation to get the power as follows:
P = 240 * 8
P = 1920 watt

Hope this helps :)