ACES EE Electromagnetism

Permanent magnets are made up of

• iron

• nickel

• soft steel

• hardened steel

Temporary magnets are made up of ___

• hardened steel

• soft steel

• soft iron

• tungsten steel

One would find a permanent magnet in ___

• relays

• earphones

• dynamic loudspeakers

• none of these

One use of a temporary magnet in ___

• motors

• electric bells

• electric buzzers

• all of these

The force acting between two magnetic poles is ___ distance between them.

• inversely proportional to the square of the

• directly proportional to the square of the

• inversely proportional to the

• directly proportional to the

The force acting between two magnet poles is ___ the relative permeability of the medium

• directly proportional to

• inversely proportional to

• independent of

• none of these

The absolute permeability of vacuum or space is ___ H/m

• 4π x 10^-12

• 4π x 10^-7

• 4π x 10^-10

• 4π x 10^-8

A bunch of magnetic lines of force is called ___

• magnetic flux density

• magnetic flux intensity

• magnetic flux

• none of these

One weber of magnetic flux is equal to ___ magnetic lines of force

• 10⁵

• 10⁶

• 10⁷

• 10⁸

Magnetic flux density is a ___

• scalar quantity

• vector quantity

• phasor

• none of these