Magnetism 2

What is the main difference between magnetically hard and soft materials?

• Hard materials can be easily magnetised and demagnetised.

• Soft materials retain their magnetism for a long time.

• Hard materials retain their magnetism for a long time.

• Soft materials cannot be magnetised.

How can you produce a uniform magnetic field using two permanent magnets?

• Place the magnets with like poles facing each other.

• Place the magnets with opposite poles facing each other.

• Place the magnets side by side with like poles aligned.

• Place the magnets in a circular arrangement.

What happens when an electric current flows through a conductor?

• It produces a gravitational field around it.

• It produces a magnetic field around it.

• It produces an electric field around it.

• It produces a sound wave around it.

Which of the following describes the construction of an electromagnet?

• A coil of wire wrapped around a plastic core.

• A coil of wire wrapped around a wooden core.

• A coil of wire wrapped around an iron core.

• A coil of wire wrapped around a copper core.

What is the shape of the magnetic field pattern around a straight wire carrying a current?

• Circular loops around the wire.

• Straight lines parallel to the wire.

• Elliptical loops around the wire.

• Randomly oriented lines around the wire.

What is the force experienced by a charged particle moving in a magnetic field when its motion is not parallel to the field?

• No force is experienced.

• A force is experienced perpendicular to both the velocity and the magnetic field.

• A force is experienced parallel to the velocity.

• A force is experienced parallel to the magnetic field.

How does the left-hand rule help in predicting the direction of the force on a current-carrying wire in a magnetic field?

• It uses the thumb to represent the direction of the magnetic field.

• It uses the index finger to represent the direction of the current.

• It uses the middle finger to represent the direction of the force.

• It uses the thumb to represent the direction of the force.

How does the force on a current-carrying conductor in a magnetic field change with the magnitude of the current?

• The force decreases as the current increases.

• The force remains constant regardless of the current.

• The force increases as the current increases.

• The force is independent of the current.

In a simple d.c. electric motor, what role does the magnetic field play?

• It provides the energy source for the motor.

• It creates a force that causes the motor to rotate.

• It acts as a cooling mechanism for the motor.

• It reduces the friction in the motor.

What happens to the magnetic field strength inside a solenoid if the number of turns is doubled?

• The magnetic field strength is halved.

• The magnetic field strength remains the same.

• The magnetic field strength is quadrupled.

• The magnetic field strength is doubled.