EMT UNIT 4-I

In a pure inductive circuit, the current

• lags emf by angle 90

• lags emf by 180

• leads emf by 90

• leads emf by 180

what will be the current I in a circuit if total moving Charge is q

• dq/dt

• -dq/dt

• qt

• none

According to the laws of electromagnetic induction

 $\nabla\times$  E is equal to

• 0

• ϵ/​ρ​.

• ​ρ/​ϵ

• −dB​/dt

An inductor stores energy in

• electric field

• coil

• magnetic field

• air

is displacement current is produced by moving charges

• yes

• no

Are the magnetic field lines in the picture correct?

• Yes, because they point from north to south.

• No, because they point from north to south (they're supposed to go the other way).

• Yes, because the North pole is on the left in all pictures.

• No, because the North pole is on the left in all pictures (it's supposed to be on the right).

Which scientist created a mathematical formula to explain how a current is induced by a magnetic field?

• Oersted

• Farraday

• Maxwell

• Tesla

___ Law says that the Induced current is proportional to the change of magnetic flux 

• Lenz'
• Faraday's
• Ampere's

In 1831 who discovered electromagnetic induction?

• Thomas Edison
• Nikola Tesla
• Michael Faraday

Magnetic flux is related to magnetic field strength by the formula

• Φ=BA

• Φ=BA²

• Φ=B/A

• Φ=B/A²