# Electricity help, calculating the current

1. Jan 30, 2008

### ella_101

In a motor vehicle, a relay is used to switch the 12 V , 60 W headlight on and off.

The resistance of the relay coil is 150 ohms . Calculate the current in the relay coil when it is connected to a 12 V supply.

2. Jan 30, 2008

### blindside

On this site it seems people prefer to encourage independent thought rather than just give the solution, but I'm not sure there's much else to say here. The relations relevant at this level are:

$$V = IR$$

$$P = IV$$

Last edited: Jan 30, 2008