Magnetic Field of a Wire
Class 10 Science: magnetic effects of electric current
Pass a current through a straight wire and watch the compasses around it turn. Reverse the current, show the field lines and test the right-hand thumb rule.
Words to know
- Magnetic field
- The space around a magnet or a current where its magnetic force can be felt.
- Field lines
- Lines that show the direction of the field. Around a straight wire they are circles.
- Right-hand thumb rule
- Hold the wire in your right hand with the thumb along the current: your fingers curl in the direction of the field.
- Compass
- A small magnet needle that points along the magnetic field.
- Oersted
- The scientist who first saw a compass needle move near a wire carrying current (1820).
Quick check
Answer 3 questions to check what you learned.
Try at home
With an adult, hold a compass under a wire connected to a cell and a switch. Press the switch for a moment. Which way does the needle move? Swap the cell around.