SP12 & 13 Magnetism and Electromagnetism

Magnets affect each other by:

• attracting each other when opposite poles are near and repelling when like poles are near

• repelling each other when opposite poles are near and attracting when like poles are near

• only attracting each other regardless of the poles

• only repelling each other regardless of the poles

The difference between permanent and induced magnets is:

• Permanent magnets retain their magnetism without external influence, while induced magnets require an external magnetic field to become magnetized.

• Permanent magnets require an external magnetic field to become magnetized, while induced magnets retain their magnetism without external influence.

• Both permanent and induced magnets require an external magnetic field to become magnetized.

• Neither permanent nor induced magnets require an external magnetic field to become magnetized.

Permanent and temporary magnetic materials are used in various applications. Which of the following is a use of permanent magnetic materials?

• Used in electric motors

• Used in transformers

• Used in temporary holding devices

• Used in magnetic resonance imaging (MRI)

The shapes of magnetic fields, including variations in strength, can be described as:

• circular and uniform

• linear and constant

• irregular and varying

• spiral and decreasing

Describe how the shape of magnetic fields can be shown using plotting compasses.

• By observing the direction of the compass needles

• By measuring the strength of the magnetic field

• By calculating the magnetic flux

• By using a magnetometer

Explain how a magnetic compass can be used as evidence for the Earth’s magnetic core.

• A magnetic compass aligns with the Earth's magnetic field, indicating the presence of a magnetic core.

• A magnetic compass measures the Earth's gravitational pull, suggesting a magnetic core.

• A magnetic compass detects seismic waves, proving the existence of a magnetic core.

• A magnetic compass shows the Earth's rotation speed, which is influenced by the magnetic core.

Recall that a current can create a magnetic effect.

• True

• False

Relate the shape and direction of the magnetic field around a straight wire to the direction of the current.

• The magnetic field forms concentric circles around the wire, and its direction is determined by the right-hand rule.

• The magnetic field forms a straight line parallel to the wire, and its direction is opposite to the current.

• The magnetic field forms concentric circles around the wire, and its direction is determined by the left-hand rule.

• The magnetic field forms a spiral around the wire, and its direction is determined by the right-hand rule.

Recall the factors that affect the strength of the magnetic field around a wire.

• Current flowing through the wire

• Distance from the wire

• Material of the wire

• All of the above

The magnetic field inside a coil of wire carrying a current is:

• uniform and parallel to the axis of the coil

• non-uniform and parallel to the axis of the coil

• uniform and perpendicular to the axis of the coil

• non-uniform and perpendicular to the axis of the coil