Magnetic Field Strength MCQ [Free PDF] – Objective Question Answer for Magnetic Field Strength Quiz

1. What is a permeable substance?

A. Any good conductor
B. Any bad conductor
C. Any strong magnet
D. Any substance through which the magnetic lines of force can pass easily

Answer: D

A permeable substance is one through which the magnetic lines of force can pass easily.

 

2. ______ Are materials having good retentivity?

A. Strong magnets
B. Weak magnets
C. Temporary magnets
D. Permanent magnets

Answer: D

Materials with good retentivity are permanent magnets because they can retain magnetism even when no external magnetic field is present.

 

3. Magnetic field exists along which of the following?

A. Moving charges
B. Stationary charges
C. Copper
D. Iron

Answer: A

Moving charges have a magnetic field associated with them because they have magnetic flux lines associated with them.

 

4. Magnetomotive force is equal to__________________

A. current × number of turns
B. current / number of turns
C. current / number of turns per unit length
D. current × number of turns per unit length

Answer: A

MMF is the ability to produce flux and is equal to the product of current flowing and the number of turns.

 

5. Unit of MMF is ______________

A. A/m
B. A-m
C. A
D. unitless

Answer: C

MMF is equal to the product of the current flowing and the number of turns.
unit of Magnetomotive force = unit of current = A or ampere.

 

6. When a bar magnet is broken into two pieces, which of the following are true?

A. The magnet loses its magnetism
B. The magnet has only the north pole left
C. The magnet has only the south pole left
D. The magnet turns into two new bar magnets

Answer: D

When a bar magnet is broken into two pieces, it forms two different bar magnets. This happens because the broken pieces of the magnet form a separate north and south pole for itself as monopoles do not exist.

 

7. When an electric current flows into the page, what is the direction of the magnetic field?

A. Clockwise
B. Anti-clockwise
C. Cannot be determined
D. Parallel to the current

Answer: A

When the current flows into the page, the magnetic field is clockwise because of the right-hand thumb rule, we orient our thumb into the page and our fingers curl in the clockwise direction.

 

8. When an electric current flows out of the page, what is the direction of the magnetic field?

A. Clockwise
B. Anti-clockwise
C. Cannot be determined
D. Parallel to the current

Answer: B

When the current flows out of the page, the magnetic field is anti-clockwise because of the right-hand thumb rule, we orient our thumb out of the page and our fingers curl in the anti-clockwise direction.

 

9. The relation between the direction of current and the direction of the magnetic field is?

A. Same direction
B. Opposite direction
C. Perpendicular
D. Unrelated

Answer: C

When a conductor carries a certain value of current, the force developed in the conductor, the current in the conductor, and the magnetic field in the conductor is mutually perpendicular to each other.

 

10. Permeability of free space is also known as _________

A. Magnetic constant
B. Electric constant
C. Electrostatic constant
D. Magnetostatic constant

Answer: A

The permeability of free space is also known as the magnetic constant. The permittivity of free space is the electrostatic constant.

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