Quiz sheet for magnetism

If an air gap is introduced to a complete magnetic circuit made of a magnetic material, the flux will tend to: 

A) decrease

B) increase

C) remain constant

D) reduce to zero

ANSWER: A

Ferromagnetic materials are:

A) not influenced by a magnetic field

B) manufactured from aluminium

C) influenced by a magnetic field

D) manufactured from copper

ANSWER: C

Ferromagnetic materials that have a high retentivity are called hard magnets and are used in: 

A) motors

B) transformers

C) relays

D) permanent magnets

ANSWER: D

If a conductor is carrying current in a magnetic field: 

A) a voltage is produced in the conductor

B) the first finger indicates the direction

C) the force is independent of flux density

D) a force is developed on the conductor

ANSWER: D

If the area of a flux path increases the reluctance will: 

A) increase

B) decrease

C) remain constant

D) fall to zero

ANSWER: B

If the magneto motive force (MMF) to a magnetic circuit is decreased and the reluctance remains constant, the magnetic flux will: 

A) increase

B) decrease

C) remain constant

D) fall to zero

ANSWER: B

Iron and iron alloys are said to be:

A) ferromagnetic

B) diamagnetic

C) paramagnetic

D) alnico

ANSWER: A

Ferromagnetic materials

A) Made of copper

B) Influence a magnetic field

C) Are made of alumimium

D) Influence a voltage field

ANSWER: B

The assumed direction of magnetic flux lines is said to be:

A) from north pole to south pole

B) from north pole to north pole

C) from south pole to south pole

D) from south pole to north pole

ANSWER: A

The items used to extend the life of stored magnets are called:

A) Keepers

B) Holders

C) Retentivity extenders

D) Containers

ANSWER: A

Wrought iron and mild steel can be operated efficiently at a higher flux density than:

A) Stainless Steel

B) Cast Iron

C) Silicon Steel

D) Permalloy

ANSWER: B

A ferromagnetic material has high:

A) permeability.

B) permability

C) permiabilty

D) reluctance

ANSWER: C

A material with a high reluctance will ______ the establishment of magnetic flux.

A) oppose

B) control

C) generate

D) concentrate

ANSWER: A

Magnetic properties state that like magnetic poles ______ each other

A) repel

B) attract

C) destroy

D) complement

ANSWER: A

Magnets are classified as either ______ magnets or ______ magnets.

A) permanent, temporary

B) temporary, electro

C) electro, induced

D) induced, temporary

ANSWER: A

Strength of magnetic field is defined as the:

A) number of field lines passing through surface

B) electric field lines passing the loop

C) current through surface

D) number of electrons passing a specific point per unit time

ANSWER: A

A an example of a material which will have a magnetic field induced into it whilst under the influence of an adjacent magnet is:

A) soft iron

B) copper

C) wood

D) aluminium

ANSWER: A

A material with a high permeability will easily ______ magnetic flux.

A) produce

B) concentrate

C) oppose

D) stop

ANSWER: A

Magnetic flux is measured in:

A) Webers.

B) Teslas.

C) Henries.

D) Ohm's.

ANSWER: A

Retentivity is an indication of how much:

A) residual magnetism a material will have.

B) magnetism is required to magnetise a material.

C) magnetism is required to de-magnetise a material.

D) residual magnetism a material will lose

ANSWER: A


Last modified: Tuesday, 1 June 2021, 9:45 AM