A window air conditioner's label reads 960 W. The wall supply is 120 V. The label does not state the current the unit draws. But P = IV already ties power, current, and voltage together, so the current can be calculated.
P = IV holds three quantities. Given any two of them, the third follows.
Here the power and the voltage are known, and the current is wanted. So make I the subject.
Start from P = IV.
Divide both sides by V. On the right, V cancels: P/V = I.
Then swap the sides, so the wanted quantity stands first.
The steps of the calculation stay the same as always; the rearrangement is written as its own step.
A window air conditioner is rated 960 W on a 120 V supply. Calculate the current it draws.
Write down the values in the question:
P = 960 W
V = 120 V
I = ?
Write down the equation:
P = IV
Make I the subject:
I = P/V
Substitute in the values:
I = 960/120
Simplify:
I = 8.0 A
The air conditioner draws 8.0 A from the supply.
A 900 W coffee maker runs on 120 V. Enter its current in amperes.
A 168 W e-bike charger runs on 42 V. Enter its current in amperes.
A 240 W TV runs on 120 V. Enter its current in amperes.
The same air conditioner on its fan-only setting is rated 60 W, still on the 120 V supply. Calculate the current it draws.
Write down the values in the question:
P = 60 W
V = 120 V
I = ?
Write down the equation:
P = IV
Make I the subject:
I = P/V
Substitute in the values:
I = 60/120
Simplify:
I = 0.5 A
On its fan-only setting, the air conditioner draws 0.5 A.
A 300 W slow cooker runs on 120 V. Enter its current in amperes.
A 54 W car headlight runs on 12 V. Enter its current in amperes.
A 108 W power drill runs on 18 V. Enter its current in amperes.
A vacuum cleaner is rated 1440 W on a 120 V supply. Calculate the current it draws, in A.
A leaf blower is rated 720 W on a 120 V supply. Calculate the current it draws, in A.
An EV trickle charger is rated 1200 W on a 240 V supply. Calculate the current it draws, in A.