Harmsy's Physics

Prefixes in Use

Here is a prefix in use:

e.g. A 2·3 kW kettle is connected to the 230 V mains. What current flows through its heating coil?

P = I × V

So I = P / V

I = 2,300 / 230

I = 10 amps

2·3 kW needs changing into 2,300 W.

If we had left the power as 2·3, our answer would have been 0.01 A - way too small for a kettle!

Whenever you see a prefix in front of a unit, remember to change the number by the correct amount!

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