Electromagnetic induction

Question 1

Magnetic flux

Answer 1

BAcos(theta)
unit is weber

Question 2

dimentional unit for magnetic flux

Answer 2

[M L^2 A^-1 T^-2]

Question 3

what is electromagnetic induction

Answer 3

inducing electricity by magnetism

Question 4

what is the motion which is responsible for the generation of electric current in the coil?

Answer 4

relative motion

Question 5

faraday first law of electromagnetic induction

Answer 5

when a magnetic field changes, it induces an electromotive force (EMF) in a conductor

Question 6

faraday second law of electromagnetic induction

Answer 6

1)The magnitude of the induced emf is equal to the rate of change of magnetic flux linked with the closed circuit
2)EMF= - (dΦ/dt)*N

Question 7

Flux can be varied by changing

Answer 7

(i) The shape of the coil (A changes)
(ii) The strength of the magnetic field (B changes)
(iii) The orientation of the coil (0 changes)

Question 8

Lenz’s Law

Answer 8

the direction of induced current is such that it opposes the cause which produces

Question 9

when a north pole of a magnet is brought near a loop it induce the current in the direction of

Answer 9

anti clockwise

Question 10

when a south pole of a magnet is brought near a loop it induce the current in the direction of

Answer 10

clockwise

Question 11

motional EMF

Answer 11

Blv
l==>length
v==>velocity

Question 12

EMF induced in self inductance

Answer 12

E= - d(Nφ)/dt = - d(LI)/dt

Question 13

EMF induced in mutal inductance

Answer 13

E= -d(Nφ)/dt = - d(MI)/dt

Question 14

Inductance depends on

Answer 14

1) geometry of coil
2) intrinsic material property

Question 15

mutual inductance when I2 current is setup to S2

Answer 15

M12= μn1n2* lpi(R1)^2
where
n1–>no of turns in coil 1
n2–>no of turns in coil 2
l–> length of coil 1
R1–> radius of coil 1

Question 16

m12=

Answer 16

m21

Question 17

in mutual inductance the emf induced depends on

Answer 17

1) rate of change of current
2) mutual inductance of the coil

Question 18

self inductance (L) Formula

Answer 18

L=μn^2A*l
where
n–> no of turns
A–> cross sectional area
l–> length of solenoid

Question 19

what is the direction of induced current in self inductance

Answer 19

opposite to the source current

Question 20

what do you mean by self inductance

Answer 20

Self-inductance is the property of the current-carrying coil that resists or opposes the change of current flowing through it

Question 21

work done in self inductance

Answer 21

W=1/2LI^2
where
L–> self inductance
I–> current
! This stored as magnetic potenial energy

Question 22

The value of the voltage generated on ac gererator depends on

Answer 22

1)The number of turns in the coil.
2)strength of the magnetic field.
3)The speed at which the coil or the magnetic field rotates.

Question 23

EMF produced in ac generator

Answer 23

emf=wNBA sin(wt)
w–>angular velocity
wNBA–> MAX emf