4 1 simple phenomena of magnetism

Magnets are objects with north and south poles. They attract magnetic materials and can attract or repel other magnets.

The two poles of a magnet are the north and south poles.

True. Opposite poles attract.

Like poles have the same polarity (e.g. north and north) and they repel each other.

Unlike poles have opposite polarities (e.g. north and south) and attract each other.

A magnetic material experiences an attractive force when placed in a magnetic field and can be magnetised to form a magnet.

Non-magnetic materials do not experience a force when placed in a magnetic field.

True. Only a magnet can repel another magnet.

To test whether a material is a magnet, it should be brought close to a known magnet. If it can be repelled by the known magnet, then the material itself is a magnet.

False. Opposite poles attract.

Permanent magnets produce their own magnetic field and do not lose their magnetism.

Induced magnetism is when a magnetic material is placed in a magnetic field and the material can temporarily be turned into a magnet.

Magnetic materials are materials that are attracted to a magnet.

False. Induced magnets lose most/all of their magnetism quickly after being removed from the magnetic field.

When magnetism is induced in a material, one end of the material will become a north pole, and the other end will become a south pole.

False. Aluminium is not a magnetic material.

Iron, cobalt, nickel, and steel (an alloy containing iron) are examples of magnetic materials.

To determine which pole is induced at one end of a magnetic material, hold a south pole near that end. If the end is repelled, it is a south pole. If it attracts, it is a north pole.

Any material other than iron, cobalt, nickel, and steel (or alloys containing these metals) is a non-magnetic material. For example, aluminum, copper, wood, plastic, etc.

False. The iron paperclip, a magnetic material, can only be attracted by a magnet, not repelled.

A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material.

A uniform magnetic field is a magnetic field that has the same strength and direction at all points.

In a uniform magnetic field, the magnetic field lines are equally spaced, and all arrows point in the same direction.

Magnetic field lines are lines drawn to represent the strength and direction of a magnetic field.

Two rules for drawing magnetic field lines are:

True. The magnetic field is strongest at the poles of a bar magnet, where the magnetic field lines are closest together.

Closely spaced magnetic field lines indicate a strong magnetic field.

Widely spaced magnetic field lines indicate a weak magnetic field.

Magnetic forces are caused by interactions between magnetic fields.

To represent the fact that a bar magnet's field weakens with distance from the magnet, the field lines get further apart further from the bar magnet.

The two principal ways of plotting the magnetic field around a bar magnet are using iron filings and using plotting compasses.

To plot magnetic field lines using iron filings:

To plot magnetic field lines using a plotting compass:

True. The direction of the magnetic field line plotted using a compass is the same as the direction of the plotting compass.

After creating a chain of dots using a plotting compass, you need to remove the compass and link the dots using a smooth curve to represent the magnetic field line.

To plot multiple magnetic field lines around a bar magnet, you need to repeat the process of using the plotting compass several times, starting from different points on the magnet.

False. The needle points in the same direction as the arrows on the field lines.

True. The magnetic field is stronger at the magnet's poles, so more iron filings will gather here.