A vacuum cleaner has a maximum power consumption of 1000 W and is powered by 240 Volts. What is the current used?

• A. 24 amps
• B. 4.17 amps
• C. 0.24 amps
• D. 2.0 amps

Answer: (B)

Power, voltage, and current are linked by the relationship P = V × I. If you know the power and the voltage, you can find the current with I = P / V. Here, the vacuum cleaner’s maximum power is 1000 W and it runs on 240 V, so the current drawn is 1000 / 240, which comes to about 4.17 A. This makes sense because 240 V multiplied by roughly 4.17 A gives the rated 1000 W.

If you imagine other currents, they’d imply different power levels at the same voltage (for example, a much larger current would mean a much higher power, and a much smaller current would mean much less power), which helps confirm why the calculated value is appropriate.