Left Hand Rule for Coils

The direction of the magnetic field created by a coil depends upon the direction of the current flowing through the coil. How do we know where the north pole will be? There is an easy method to determine this. The method is called the Left Hand Rule for Coils.

Left Hand Rule For Coils: Look at the left hand side figure. Imagine that you are grabbing the coil with your left hand in such a manner that your fingers are aligned with the direction of the current flow. Now stick your thumb out. Your thumb will point to the direction where the north pole will be located.

The right hand side figure is also demonstrating the application of the Left Hand Rule for coils. In this case, the direction of current flow has been reversed, so you need to hold (still using your left hand) the coil in a different manner – as shown. Again, your thumb points to the north pole.