Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A magnet has two ends called poles: the North Pole () and the South Pole ().
Magnetic forces are 'non-contact forces', meaning they can push or pull objects without touching them.
The Law of Magnetism states that opposite poles attract ( and pull together) and like poles repel ( and or and push apart).
Magnetic materials include metals like Iron (), Nickel (), and Cobalt (). Most other materials, like plastic, wood, and aluminum (), are non-magnetic.
The magnetic field is the invisible area around a magnet where the magnetic force () can be detected.
📐Formulae
iconography
iconography
(The force gets weaker as the distance increases)
💡Examples
Problem 1:
Tim brings the North pole () of a bar magnet close to the North pole () of another bar magnet. What force will he feel?
Solution:
A force of repulsion.
Explanation:
According to the laws of magnetism, like poles (the same poles) push away from each other. Therefore, .
Problem 2:
Sarah has a mixture of steel (iron-based) paperclips and plastic beads. How can she separate them quickly using physics?
Solution:
Use a magnet to attract the steel paperclips.
Explanation:
Steel contains Iron (), which is a magnetic material. The plastic beads are non-magnetic. The magnet will apply a magnetic force to the steel but not the plastic.
Problem 3:
If the distance between two attracting magnets is increased from to , what happens to the strength of the pull?
Solution:
The magnetic pull becomes much weaker.
Explanation:
Magnetic force is strongest at the poles and weakens rapidly as the distance between the magnet and the object increases.