Physics

Magnetism and Electromagnetism

1,019 Questions

This hub provides practice questions on magnetism and electromagnetism. It covers magnetic flux density, electromagnets, magnetic lines of force, and electromagnetic induction. These physics concepts frequently appear in technical and non-technical competitive exams.

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Magnetism and Electromagnetism Questions

Multiple choice

Which has a stronger magnetic field?

  1. a solenoid

  2. an electromagnet
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An electromagnet is a solenoid with a ferromagnetic core, which significantly concentrates and strengthens the magnetic field compared to a hollow solenoid. Therefore, an electromagnet is stronger.

Multiple choice physics electromagnetism magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop field due to a current carrying coil oersted experiment

Consider an experiment where Electric current is flowing in a wire. It is observed that clockwise magnetic field is produced around the wire. A teacher decides to reverse the direction of source battery which results in reversal of electrical current. What will be the effect on magnetic field?

  1. Magnetic field disappears

  2. Direction of field lines reverse

  3. Field lines changes direction to parallel to wire

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using Right Hand thumb rule, as current direction reverses, you need to reverse the hand and direction of magnetic field reverses.

Multiple choice physics magnetic effect of electric current magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop field due to a current carrying coil magnetic field lines due to current magnetic field due to current carrying conductor magnetic field on the axis of a toroid

Why does toroid have a higher magnetic field than a solenoid?

  1. It is magnetically efficient.

  2. It is a straight core.

  3. It has an open loop core.

  4. It has a closed loop core.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Due to the symmetry and being closed loop core.
Totoid has higher magnetic field and thus higher inductor and Q-facator
Multiple choice physics electromagnetism magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop field due to a current carrying coil oersted experiment field due to a current carrying conductor magnetic field due to a straight current carrying conductor magnetic field lines due to current

Define Electromagnetism

  1. The study of attraction or repulsion between two magnets is called electromagnetism

  2. The study of electric effects due to magnetic interaction is called electromagnetism

  3. The study of magnetic effects produced due to electric current is called electromagnetism

  4. The study of magnetic effects produced due to electric charge is called electromagnetism
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Electromagnetism is study of various phenomenon related to electricity and magnetism. 

Multiple choice physics electromagnetism magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop field due to a current carrying coil oersted experiment field due to a current carrying conductor magnetic field due to a straight current carrying conductor magnetic field lines due to current

How can you determine direction of magnetic field lines around a current carrying conductor

  1. Left hand Thumb Rule

  2. Right Hand Thumb Rule

  3. By rotating the conductor

  4. Using sonometer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Direction of magnetic field lines around a current carrying conductor can be found by RIght Hand Thumb Rule.

Multiple choice eddy currents motional emf electromagnetic induction electromagnetic induction and alternating currents physics

Identify the wrong statement

  1. Eddy currents are produced in a steady magnetic field

  2. Eddy currents can be minimized by using laminated core

  3. Induction furnace uses eddy current to produce heat

  4. Eddy current can be used to produce breaking force in moving trains
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eddy currents comes in picture only when there is change in linked magnetic flux. 

They can be created when a conductor is moving through a magnetic field, or when the magnetic field surrounding a stationary conductor is varying i.e. anything which results in the conductor experiencing a change in the intensity or direction of a magnetic field can produce eddy currents.

Thus  $A$ is the correct option.

Multiple choice eddy currents motional emf electromagnetic induction electromagnetic induction and alternating currents physics

Identify the wrong statement.

  1. Eddy currents are produced in a steady magnetic field.

  2. Eddy currents can be minimized by using laminated core.

  3. Induction furnace uses eddy current to produce heat.

  4. Eddy current can be used to produce breaking force in moving trains.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eddy currents comes in picture only when there is change in linked magnetic flux. Thus statement A is wrong.

Multiple choice eddy currents motional emf electromagnetic induction electromagnetic induction and alternating currents physics

Which of the following law follows when eddy currents are generated?

  1. Lenz's law

  2. Gauss's law

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field.By Lenz's law, an eddy current creates a magnetic field that opposes the change in the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field.Lenz law, the current swirls in such a way as to create a magnetic field opposing the change; for this to occur in a conductor, electrons swirl in a plane perpendicular to the magnetic field.

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Multiple choice eddy currents motional emf electromagnetic induction electromagnetic induction and alternating currents physics

Which of the following is true in context of Eddy currents?

  1. By Lenz's law, an eddy current creates a magnetic field that opposes the magnetic field that created it.

  2. Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction

  3. Eddy currents are a cause of energy loss in alternating current (AC) inductors, transformers, electric motors and generators etc.

  4. All of the above

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction,are a cause of energy loss in alternating current (AC) inductors, transformers, electric motors and generators etc.

By Lenz's law, an eddy current creates a magnetic field that opposes the magnetic field that created it.
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