Electromagnetic Induction

Question 1

EMI

Answer 1

Phenomenon of production of induced EmF due to which magnetic Flux linked with a closed circuit

Question 2

Faraday’s law

Answer 2

Magnitude of induced emf is equal to time rate of change of magnetic Flux linked with thr closed circuit
E = -Ndø/dt

Question 3

Flux can be varied by

Answer 3

Changing A,B or ø

Question 4

Magnetic flux

Answer 4

Total no of field lines crossing the surface normally
Ø(B) = B.A

Question 5

Flux unit

Answer 5

Weber

Question 6

Gauss’s law of magnetism

Answer 6

Total magnetism Flux throug hany closed system is 0
Ø(b) = sigma B.A = 0

Question 7

Lenz’s law

Answer 7

Polarity of induced emf is such that it tends to produce a current which opposes change in Flux that produced it

Question 8

When fluc changes from Øa to Øb in time t, avg Emf E=

Answer 8

E = -N(Øb-Øa)/t

Question 9

Motional EMF

Answer 9

Emf induced across the ends of a conductor due to its motion in B

Question 10

Motional emf E=

Answer 10

BlV where dx/dt = -V in decreasing dir of x

Question 11

Motionless emf from Lorentz force & energy consideration

Answer 11

E = VBl

Question 12

Motional emf I =

Answer 12

BlV/R

Question 13

Motional emf F =

Answer 13

B²l²V/R

Question 14

Motional emf P =

Answer 14

FV = B²l²V²/R = powerloss[P(j)]

Question 15

Mechanical energy is converted to

Answer 15

Electrical energy then to thermal energy. So energy I’d conserved

Question 16

Inductance

Answer 16

Phenomenon of production of induced emf in a coil by changing current through itself or neighbouring coil

Question 17

Inductance fm

Answer 17

Nø = KI where K is inductance

Question 18

Self Inductance + fm

Answer 18

Phenomenon of inducing EMF in a coil by changing I through itself
NØ = LI

Question 19

Self Inductance by Faraday’s law

Answer 19

E = -LdI/dt
-ve sign is because self induced emf opposes change in current through itself(back emf)

Question 20

Self Inductance of a long solenoid

Answer 20

L = myu°N²/l pi r²

Question 21

Self Inductance depends on:

Answer 21

N²(turns)
Area
Myu

Question 22

Slope of Ø-I graph gives

Answer 22

Self inductance

Question 23

Mutual inductance + fm

Answer 23

Phenomenon os inducing emf in a coil by changing current through te neighboring coil
NØ = mI

Question 24

Emf by faraday’s law for mutual inductance

Answer 24

E = -mdI/dt
-ve as Ø opposes emf

Question 25

Mutual inductance of 2 long solenoids

Answer 25

m = myu°n1n2L pi r²

Question 26

Mutual inductance depends on

Answer 26

M prop N1N2(Turns)
M prop A (Area)
M prop 1/l distance btw solenoids
Relative orientation changes as we rotate it

Question 27

Inductive coupling

Answer 27

When I flows through 2 nearby coils simultaneously, Flux linked with 1 coil will be sum of fluxes which exists independently
E1 = -LdI1/dt - MdI2/dt
N1Ø1/I2 = N2Ø2/I1

Question 28

Coefficient of coupling k of 2 coils

Answer 28

K = m/(L1L2)½

Question 29

Energy stored in an inductor

Answer 29

E = ½LI²

Question 30

AC generator

Answer 30

Converts mechanical energy to electrical energy
Principle: change in Flux induces emf in it

Question 31

AC generator emf

Answer 31

E = E°sinwt(E°=wNBA)
E° = amplitude of induced emf

Question 32

Alternating emf & alternating current

Answer 32

Direction of induced emf and current varies periodically with time
E = E°sin(2pi nyu t)

Question 33

Factors on which mutual inductance depends on

Answer 33

N
Area
Distance btw solenoids(inversely)
Relative orientation