8 a)

b)

10

11

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Module-II

An iron ring of mean diameter 10cm is uniformly wound with a coil of 2000
turns. When a current of 0.25A is passed through the coil a flux density of
0.4T is set up in the iron ring. Find i) the magnetizing force and ii) the
relative permeability of iron.
Define i) self-inductance of a coil ii) coefficient of coupling and iii) relative
permeability

OR
Two coils A and B have 12000 turns and 14000 turns respectively. 80% of
the flux produced by coil A links with coil B. A current of 6A in coil A
produces 0.05mwb in coil A while the same current in coil B produces
0.085mwb in coil B. Calculate i) Mutual inductance and ii) Coefficient of
coupling.

۸100101-1

Coil A having resistance of 20 Q and inductance of 0.2 H is connected in
series with another coil B having resistance of 15Q and inductance of 0.1H.
The two coils in series are fed from 220V, 50 Hz, single phase power
supply. Determine (i) the voltage across each coil (ii) power dissipated in
each coil (iii) power factor of the whole circuit.

OR
Three similar coils connected in star draw a total power of 1.5kW at a power
factor of 0.2 lagging from a 3 phase 400V, 50Hz power supply. Calculate

the resistance and inductance of each coil

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