Question

a bar magnet is moved in and out in coil i.e. connected to a sensitive centre zero meter as shown in figure below.
the meter needle swings when to the left when the magnet is moving towards the coil
1. how the needle behaves when the bar magnet is at rest?
a) swing towards left
b) swing towards right
c) does not move
d) swing towards left then come back
2. how the needle behaves when the bar magnet is at rest
and coil moving away from magnet?
a) swing towards left
b) swing towards right
c) does not move
d) swing towards left then come back
3. The magnetic fields lines outside a bar magnet
a) Originate from the South pole and end as its North pole
b) Originate from the North pole and end as its East pole
c) Originate from the North pole and end as its South pole
d) Originate from the South pole and end as its West pole
4. The North Pole of Earth's Magnet is in the:
a) Geographical South
b) Geographical East
c) Geographical West
d) Geographical North​

Answer 1

Answer:

3. c) originate forom north pole and end as its south pole

4. a) geographical south pole

Answer 2

Solution;-

1. Option (C) - does not move

               By Faraday's law ,

                           ∈ = −dΦB/dt

• Since, neither the magnet nor the coil is moving so the net induced current in the coil is zero.
• Hence, there is no swing in the centre zero meter.

2. Option (B) -  Swings towards left

              By Faraday's law ,

                         ∈ = −dΦB/dt

• The coil moves away from the north pole of the magnet  Hence, the current induced in the coil is clockwise to oppose the movement i.e to attract the magnet towards it.
• Using the right hand thumb rule, the direction is clockwise. So, the needle swings right.

3. Option (C) -  Originate from the North pole and end as its South pole

4. Option (A) - Geographical South