Emi-tb

Question 1

Conclusions from Faradays experiment

Answer 1

• experiment 1: - It shows that it is the relative
  motion between the magnet and the coil that is
  responsible for generation (induction) of electric
  current in the coil.
• experiment 2: - relative motion b/w coils induces the electric current.
• experiment 3: -
  Relative motion is not a necessary requirement.
  momentary deflection is shown when the key is pressed but no deflection is observed when the key is pressed continuously.
  deflection increases dramatically when the iron rod is inserted.

Question 2

final conclusion from the experiments

Answer 2

The magnitude of the induced emf in a circuit is equal
to the time rate of change of magnetic flux through the
circuit.

Question 3

Consider Experiment 6.2.
(a) What would you do to obtain
a large deflection of the galvanometer?

Answer 3

(a) To obtain a large deflection, one or more of the following steps can be taken:
(i) Use a rod made of soft iron inside the coil C2.
(ii) Connect the coil to a powerful battery, and
(iii) Move the arrangement rapidly
towards the test coil C1
.
,

Question 4

Consider Experiment 6.2.
(b) How would you demonstrate
the presence of an induced current in the absence of a galvanometer?

Answer 4

Replace the galvanometer by a small bulb, the kind one finds in a
small torch light. The relative motion between the two coils will cause
the bulb to glow and thus demonstrate the presence of an induced
current.

Question 5

A closed loop is held stationary in the magnetic field between the
north and south poles of two permanent magnets held fixed. Can
we hope to generate current in the loop by using very strong
magnets?

Answer 5

No. However strong the magnet may be, current can be induced
only by changing the magnetic flux through the loop.

Question 6

A closed loop moves normal to the constant electric field between
the plates of a large capacitor. Is a current induced in the loop
(i) when it is wholly inside the region between the capacitor plates
(ii) when it is partially outside the plates of the capacitor? The
electric field is normal to the plane of the loop.

Answer 6

No current is induced in either case. Current can not be induced
by changing the electric flux.

Question 7

motional emf

Answer 7

The induced emf Blv is called motional emf.

Question 8

fundamental significance of Faradays laws

Answer 8

• to explain the existence of induced emf or
  induced current, we must assume that a time-varying magnetic field
  generates an electric field.
• charges in motion (current) can exert force/torque on a stationary magnet.
• Conversely, a bar magnet in motion (or more generally, a changing
  magnetic field) can exert a force on the stationary charge. This is the
  fundamental significance of the Faraday’s discovery. Electricity and
  magnetism are related.

Question 9

factors affecting magnetic flux

Answer 9

• by changing value of B or A
• By changing the shape of the coil.
• Changing the angle b/w B and A.

Question 10

Factors affecting inductance in a capacitor

Answer 10

• plate area
• plate separation.
• dielectric constant k of the intervening medium.

Question 11

inductance is a ____quantity

Answer 11

scalar

Question 12

dimensional formula of inductance

Answer 12

ML2T-2A-2

Question 13

factors affecting mutual inductance

Answer 13

depends on the separation as well as their relative orientation.