ELE101/102 Dept of E&E,MIT Manipal 1

Tutorial - Electromagnetic Induction

[1] A wire of length 1 m moves at right angles to its length at 60 m/sec in a uniform magnetic field of density 1 Tesla. Calculate the emf induced in the conductor when the direction of motion is (i) perpendicular to the field (ii) inclined at 300 to the direction of the field (iii) parallel to field

[60 V, 30 V, 0 V]

ELE101/102 Dept of E&E,MIT Manipal 2

Tutorial - Electromagnetic Induction

[2] A coil of 1500 turns gives rise to a magnetic flux of 2.5 mWb when carrying a certain current. If the current is reversed in 0.2 seconds, what is the average value of emf induced in the coil?

[37.5 V]

ELE101/102 Dept of E&E,MIT Manipal 3

Tutorial – continued ….

[3] The self-inductance of a coil of 500 turns is 0.25 H. If 60% of

the flux is linked with a second coil of 1000 turns calculate

(i) the mutual inductance of the two coils. (ii) EMF induced in

the second coil when current in the first coil changes at the

rate of 100 A / Sec

(0.3H; 30V)

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Example

[4] Coil 1 of a pair of coupled coils has a continuous current of 5A, and the corresponding fluxes 1 and 12 are

0.6mWb and 0.4 mWb respectively. If the turns are N1=500 and N2=1500, find L1, L2, M and k.

Ans:

L1 = N1 1 /I1= 0.06 H

M = N2 12 /I1= 0.12H

k = 12 / 1 = 0.667

L2 = 0.539H

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[5] Two coils with inductances in the ratio 1:4 have a

coupling coefficient k=0.6. When these coils are

connected in series aiding the equivalent inductance is

44.4mH. Find L1, L2, and M

Ans: L1 =6mH, L2 =24mH, M =7.2mH

Example

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Tutorial – continued ….

[7] Three magnetically coupled inductive coils having the following data are connected in series as shown in Figure.

L1 = 12 H; L2 = 14 H; L3 = 14 H;

k12 = 0.33; k23 = 0.37; k31 = 0.65;

Find the equivalent inductance of the circuit.

ANS: 24.87 H

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Tutorial – continued ….

[8] Two inductances each of 10 and 29 H are connected in

parallel. If the current in 10 H changes at a uniform rate of 4

A in one second, what is the rate of change of current in 29

H inductance and in the entire network?

(1.3793 Amps/s and 5.3793 Amps/s)