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

Which substances show permanent magnetism?

  1. Paramagnetic

  2. Ferromagnetic

  3. Anti-ferromagnetic

  4. Diamagnetic

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

The reason behind such magnetic behaviour is that metal ions in these substances are grouped together into domains. Each domain acts as a tiny magnet having a definite magnetic moment.

Multiple choice

Which of the following statements is/are false? a. If the force is applied in the direction of motion of the object, its speed increases. b. At the higher altitudes, the atmospheric pressure is much more than our blood pressure. c. The magnetic force between a magnet and an iron object is always that of attraction.

  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

Statement 'b' is a false statement. Thus, it is the correct option. At the higher altitudes, the atmospheric pressure is much less than our blood pressure.

Multiple choice

Which of the following statements is/are false? a. Like poles of two magnets attract each other, whereas unlike poles repel each other. b. The magnetic force exerted by one magnet on the other magnet is a non-contact force. c. An electrically charged object can exert an electrostatic force on an uncharged object.

  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
A Correct answer
Explanation

Statement 'a' is a false statement. Thus, it is the correct option. Like poles of two magnets repel each other, whereas unlike poles attract each other.

Multiple choice

The working of a dynamo is based on the principle of

  1. electromagnetic induction

  2. magnetic effect of current

  3. heating effect of current

  4. chemical effect of current

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

The working of a dynamo is based on the principle of electromagnetic induction.

Multiple choice

Displacement current is

  1. the current that comes into play in the region in which electric and magnetic field changes, and hence the electric flux is constant

  2. the current that comes into play in the region in which electric and magnetic field changes, and hence the electric flux is changing with time

  3. the current that is produced with changing electric field only

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

Displacement current (Id = ε0(dΦE/dt)) is the current that appears in regions where the electric field and electric flux are changing with time. It was introduced by Maxwell to complete Ampere's law and explains how electromagnetic waves can propagate through empty space. Option A incorrectly states that electric flux is constant - the key is that it must be changing with time.

Multiple choice

Electromagnetic waves do not transport

  1. energy

  2. electric field

  3. magnetic field

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

Electromagnetic waves transport energy (through the Poynting vector), electric fields, and magnetic fields as they propagate through space. However, they do NOT transport charge - charges are the source of EM waves but remain at their source location. This is a fundamental distinction between charged particle motion and electromagnetic wave propagation.

Multiple choice

When electric current flows through a wire, it behaves like a

  1. battery

  2. motor

  3. radar

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

When electric current flows through a wire, it generates a magnetic field around the wire, a phenomenon discovered by Oersted. This electromagnetic effect is the basis for electromagnets. The wire does not behave like a battery, motor, or radar.

Multiple choice

The relationship between magnetism and electricity is called

  1. electrocardiogram

  2. electro chemical

  3. electromagnetism

  4. electromotor
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Electromagnetism is the branch of physics studying the relationship between electricity and magnetism. Electrocardiogram measures heart activity, electrochemical relates to chemical reactions involving electricity, and electromotor is not a standard term.

Multiple choice

Like poles of two magnets

  1. attract each other

  2. repel each other

  3. neither attract nor repel

  4. first attract then repel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Like poles (north-north or south-south) of magnets repel each other, while unlike poles (north-south) attract. This is a fundamental property of magnetic fields and follows the principle that magnetic field lines from like poles diverge, creating repulsive force.

Multiple choice

In electric bells, the magnet used is

  1. permanent magnet

  2. bar magnet

  3. temporary magnet

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

Electric bells use electromagnets (temporary magnets) that become magnetic only when current flows through the coil. This temporary magnetization is essential for the bell's mechanism - the magnet attracts a hammer when energized, then releases when a contact breaks the circuit, creating the ringing action.