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Thursday, April 30, 2009

Turning effect on a current-carrying coil

In this learning outcome, it is important 4 u to really understand the whole concept. It represents the fundamental principle of how d.c motors work. In SPM physics , it always being asked in Paper1 or Paper2.
So, in this outcome, u must be able to;

-Describe how a current carrying coil in a magnetic field experiences a turning force:
To describe this, 1st u need a wire(conductor) and shape it like a coil in diagram1.

Diagram 1

Then bring this coiled wire in between a permanent magnet. After that u connect both end of the wire to a battery. As a result,current will be supplied through the coil a-b & c-d as shown in diagram 2.

Diagram 2

- From the diagram2 , current in side a-b & side c-d are in different direction.
- In side a-b, apply Fleming Left hand rule, u'll get a force acting downward.
Thus side a-b will pushed downward.

- In side c-d, applying Fleming left hand rule, u'll get a force acting upward.
This caused side c-d to move upward.

- As a result, a turning effect in both sides turn the coil rotating anticlockwise as shown in
diagram 3 below.
Diagram 3

By looking at different view, the turning effect can also be illustrated in diagram 4.

Diagram 4

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