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.

Electromagnet coresMagnetic flux densityMagnetic lines of forceElectromagnetic inductionBar magnet propertiesMagnetic materials

Magnetism and Electromagnetism Questions

Multiple choice

Electron microscope employs

  1. magnet

  2. glass lenses

  3. plane glass

  4. electromagnetic coils
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An electron microscope is a scientific instrument which uses electromagnetic coils.

Multiple choice

Directions: The following question consists of certain statements. Select the option representing the most logical sequencing of the given statements. A. Electromagnetic induction was discovered by Faraday. B. Electromagnetic induction is an electrical phenomenon. C Motors run on the principle of electromagnetic induction.
D. Motors run when electricity is switched on. E. Electromagnetic induction requires the flow of electric current. F. Motors run on electric current.

  1. ABF

  2. ABC

  3. BDA

  4. CEF
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

CEF  

Multiple choice

Which of the following are diamagnetic?

  1. C2
  2. N2
  3. O2
  4. F2

  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 1 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, both are diamagnetic. N2 (14 e-) : σ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 π2px2 π2py2 No unpaired electron, diamagnetic

O2 (16 e-) : ϭ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 π2px2 π2py2 ϭ*2pz2 No unpaired electron, diamagnetic

Multiple choice

Which of the following are diamagnetic?

  1. Be2
  2. B2
  3. C2
  4. O2
  5. F2 Select correct answer using codes given below:

  1. 1, 2 and 4

  2. 1, 3 and 5

  3. 2, 3 and 4

  4. 3 and 5

  5. 3, 4 and 5
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Be2 (8 e-) : σ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 No unpaired electron, diamagnetic.

B2 (10 e-) : σ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 No unpaired electron, diamagnetic.

O2 (16 e-) : ϭ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 π2px2 π2py2 ϭ*2pz2 No unpaired electron, diamagnetic.

Multiple choice

Directions: Pick the odd one out.

  1. Magnet

  2. Repel

  3. Attract

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

All the other words except repel are synonymous. Repel means to thrust back or away.

Multiple choice

Which of the following is not a practical use of an electromagnet?

  1. They are used in electrical appliances.

  2. It is used to measure resistance in an electric circuit.

  3. An electromagnet is used in television.

  4. They are used in magnetic separation of iron ores.

  5. They are used to prepare strong permanent magnets.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the correct option. An electromagnet is not used to measure the resistance of an electric circuit.

Multiple choice

Which of the following statements is/are false? a. The lesser the current flows through a coil, the more powerful is the electromagnet. b. Whenever current passes through a straight conductor, it behaves like a magnet. c. The magnetic field set up by the conductor is at right angles to the direction of the flow of current.

  1. Only a

  2. The a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The lesser the current flows through a coil, the more powerful is the electromagnet, is a false statement. Thus, it is the correct option. The more the current flows through a coil, the more powerful is the electromagnet.

Multiple choice

Which of the following statements is/are false? a. When a soft iron core is placed in a closed coil carrying current, it acts as an electromagnet. b. The magnitude of magnetic field decreases with the increase in the magnitude of current in the conductor. c. The amount of heat produced in a wire depends on its material, length and thickness.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The magnitude of magnetic field decreases with the increase in the magnitude of current in the conductor, is a false statement. Thus, it is the correct option. The magnitude of magnetic field increases with the increase in the magnitude of current in the conductor.

Multiple choice

Directions: Choose the best option to fill in the gaps. Seafarers' records _____ back to 1590 _____ it possible to visuallse the behaviour of one of the planet's most mysterious phenomena: its magnetic field.

  1. dating/have made

  2. to date/would make

  3. being dated/had made

  4. to be dated/are making

  5. to have been dated/will make

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

The sentence requires a participle phrase 'dating back' to modify 'records', and the verb phrase 'have made' to complete the main clause.

Multiple choice

An electric iron is based on the principle of _________________.

  1. magnetic effect of current

  2. chemical effect of current

  3. heating effect of current

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heating effect of electricity is one of the widely used effects in the world. When electric current is passed through a conductor, it generates heat due to the resistance it offers to the current flow. In iron there is a resistance wire which heats up.

Multiple choice

A transformer works on which of the following principles?

  1. Electro magnetic parade

  2. Electro magnetic induction

  3. Electro magnetic polarization

  4. Electro magnetic conduction

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

Transformers operate based on the principle of mutual induction, where a changing magnetic flux in the primary coil induces an electromotive force in the secondary coil. This is a fundamental application of Faraday's law of electromagnetic induction.

Multiple choice

Directions: Four parts of the sentence given below have been underlined. Identify the part having an error. If no part has an error, mark (5).

Discovery of the magnetic (1) effect of coils in the 19th century (2) had opened the realms of possibilities for the scientists to (3) try measuring an (4) electric current. (5) No error

  1. (1)

  2. (2)

  3. (3)

  4. (4)

  5. (5)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

While referring to specific time in the past, we should use simple past tense. Here 'had opened' should be replaced by 'opened'.