MOCK UPS 3_3

Electromagnetic induction occurs when

• an emf is induced in a magnetic flux coil.
• there is a change in magnetic flux.
• a current is induced in the coil.
• there is a magnetic flux in the coil.

The strongest part of a magnet is ……

• the bar.
• the force field.
• the poles.
• the middle.

What does the following represent?

• Uniform magnetic field directed out of page.
• Uniform magnetic field directed into the page.
• Uniform magnetic field directed upward of page.
• Uniform magnetic field directed inward of page.

According to Lenz’s law, ___________________.

• the induced emf is proportional to the magnetic field
• the direction of the induced emf is such that it will oppose the change causing it
• Fleming’s left-hand rule can be used to determine the direction of the induced emf
• the induced emf is always in the opposite direction to the magnetic field

Passing current through a solenoid will produce ___________.

• a current field
• an electric field
• a magnetic field
• nothing is produced

A permanent magnet is pushed into a coil as shown in the figure below. Which one of the following does not occur?

• The magnet losses all its magnetism.
• The magnetic field through the coil changes.
• An e.m.f. is induced in the coil.
• The direction of current induced is anticlockwise.

Figure below shown a single turn of circular shaped coil moves toward the north pole of a bar magnet. state the direction of the induced current observed by the observer.

• Downward
• Upward
• Clockwise
• Counterclockwise

Induced emf can be induced in a wire by ______________.

• a moving the wire near a magnet.
• moving a magnet near the wire.
• changing the current in a nearby wire.
• all of these.

Which of the following factors has no effect on the magnitude of induced e.m.f. in a rotating coil?

• magnetic field strength
• number of turns
• the type of coil wire
• angular velocity

The distance from center of mirror, C to the pole of mirror is given as

• 2f
• v
• u
• 2R