Question

The method of placing an iron plate between the poles of a temporary horseshoe magnet ___________.

• A. Increases the poles strength
• B. Decreases the poles strength
• C. Helps keep their magnetic properties for a longer time
• D. Does not affect the pole strength

Answer 1

The correct option is C Helps keep their magnetic properties for a longer time

The purpose of a horseshoe magnet's shape is to place the poles as close together as possible.The total magnetic flux is the same,but the field is greater, as it is spread over a smaller volume. A horseshoe is used, rather than a simpler C-shaped magnet, which is also used, because this places the maximum amount of magnetised material into the magnet, for given dimensions around the poles. A particularly large horseshoe magnet is U-shaped with long parallel sides, rather than the classical horseshoe.