In a physics demonstration, an insulated copper wire is placed directly above a magnetic compass needle, parallel to its north-south alignment. When an electric current is switched on in the wire, the compass needle deflects. Which of the following options correctly explains why this deflection occurs, and describes what happens to the compass needle when the direction of the current is reversed?
Explanation: There is a magnetic field inside the wire.
Effect of reversing current: The compass needle deflects in the opposite direction.
Explanation: There is a magnetic field around the wire.
Effect of reversing current: The compass needle deflects in the opposite direction.
Explanation: There is a magnetic field inside the wire.
Effect of reversing current: The compass needle remains deflected in the same direction.
Explanation: There is a magnetic field around the wire.
Effect of reversing current: The compass needle remains deflected in the same direction.
30 exam-style questions on CIE IGCSE Physics 4.5.3a Magnetic effect of a current and its applications. Each one has a worked solution and a mark scheme showing where the marks go.