Kuiz Fizik Tingkatan 5 Bab 4

SELAMAT DATANG Kuiz Fizik Tingkatan 5 Bab 4

KUIZ INI MENGANDUNGI 10 SOALAN

Which of the following rules is used to determine the direction of the force experienced by a straight wire carrying a current within a magnetic field?

Fleming’s Right-Hand Rule

Fleming’s Left-Hand Rule

Right-Hand Grip Rule

Lenz’s Law

None

Which of the following changes would increase the rate of rotation of a DC electric motor?

Decreasing the current supplied to the coil.

Replacing the soft iron core with an air core.

Using a coil with more turns (lilitan).

Using weaker permanent magnets.

None

In a simple DC motor, the coil continues to rotate past the vertical position even though the current is momentarily cut off. What is the reason for this continued rotation?

The magnetic field from the permanent magnets reverses.

The coil’s rotational inertia.

The power supply provides a brief surge of current.

The rotational force on the coil sides is at its maximum.

None

The force on a current-carrying wire in a magnetic field results from a 'catapult field'. In which region of this resultant field is the magnetic field weakest?

Where the field lines from the wire and the permanent magnet are in the same direction.

Along the central axis of the permanent magnet’s field.

Directly above the wire, regardless of field direction

Where the field lines from the wire and the permanent magnet are in opposite directions.

None

An ideal step-up transformer is designed to change a 12 V input to a 48 V output. If the primary coil has 50 turns, how many turns must the secondary coil have?

12.5 turns

800 turns

50 turns

200 turns

None

What is the primary purpose of the soft iron core in a transformer?

To provide electrical insulation between the primary and secondary coils.

To prevent the transformer from overheating during operation.

To concentrate and guide the magnetic flux from the primary to the secondary coil.

To step down the current while stepping up the voltage.

None

What is the key structural difference in the way the coil connects to the external circuit in an AC generator versus a DC generator?

An AC generator has more coil turns than a DC generator.

An AC generator uses slip rings, while a DC generator uses a split-ring commutator.

The coil rotates clockwise for AC output and counter-clockwise for DC output.

A DC generator uses permanent magnets, while an AC generator must use electromagnets.

None

Why will a transformer not operate if its primary coil is connected to a direct current (DC) power supply?

A DC supply produces a constant magnetic field, which does not induce a current in the secondary coil.

DC current is unable to magnetize the soft iron core.

The secondary coil is designed in a way that only allows alternating current to be generated.

The resistance of the primary coil is too high for DC to flow.

None

According to Faraday's Law of Induction, the magnitude of the induced electromotive force (e.m.f.) in a conductor is directly proportional to what?

The electrical resistance of the conductor.

The total magnetic flux contained within the coil.

The strength of the current flowing in the conductor.

The rate of change of magnetic flux through the conductor.

None

10.

When the north pole of a bar magnet is pushed towards a solenoid, a current is induced. According to Lenz's Law, what will be the magnetic polarity of the end of the solenoid closest to the approaching magnet?

North pole

South pole

It will have no magnetic polarity.

The polarity will alternate rapidly.

None

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