Page 59 - Physics_Form_4

Physics for Secondary Schools

Therefore, Switch
A A
A phenomenon associated with electric
and magnetic fields and their interaction Rheostat
is known as electromagnetism. It is the Copper wire
effect produced by the interaction of an conductor
FOR ONLINE READING ONLY
electric current with a magnetic field.
Battery
The interaction between electric and B
magnetic fields may result to a force Figure 2.1
causing the current carrying conductor to 2. Hold a magnetic compass directly
move. On the other hand, if a conductor is above conductor AB. Adjust the
moved perpendicular to a magnetic field, position of the conductor such that
a current is formed within the conductor. it is in line with the compass needle
as shown in Figure 2.2.
Magnetic field due to a current A
carrying conductor
When an electric current flows through a Conductor
conductor, it generates a magnetic field
around the conductor. Thus, around any
current carrying conductor, there is a
magnetic field. This effect is demonstrated Magnetic
in Activity 2.1. compass

Activity 2.1

Aim: To demonstrate that an
electric current flowing B
through a conductor Figure 2.2
produces a magnetic field. 3. Close the switch to allow an electric

current to flow through the circuit;
Materials:Two dry cells, switch, and observe what happens to the
rheostat, magnetic compass, compass needle. Record your
ammeter, connecting wires, observations.
copper wire conductor
4. Vary the current through the
Procedure conductor AB. Observe the compass
1. Set up an electric circuit as shown needle as the current through AB
in Figure 2.1. increases or decreases. Record your
observations.

52
Student’s Book Form Four

Physics Form 4.indd 52 14/07/2025 14:43