18.

19.

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27.

A

The area of hysteresis loop is a measure of
(^) Energy loss per cycle (B) Magnetic flux
(0 Permeance (2) Mmfper cycle

The Faraday’s law of electromagnetic induction and Lenz's law are summarized in the
equation

(^) e=LR (8) e=L di/dt
(0 e=-dy/dt (D) None of the above
The magnetic field required to reduce the residual magnetization to zero is called
(க) retentivity (B) coercivity
(C) hysteresis 0) saturation magnetisation

Distribution transformers are designed for lower
(A) _ iron losses (B) power factor
(C) copper losses (D) windage losses

The mechanical characteristics of a de motor is
(A) current versus torque
(8) efficiency versus speed
(C) current versus speed
(>) torque versus speed

What will be the number of poles to get maximum speed for an alternator ?

(A) 4 (B) 6
(0 2 (>) 8
The starting torque of a three phase induction motor is directly proportional to
(A) V ൫൦
© 17 ‏رم‎ vi?

Carbon brushes are preferred over copper brushes in de machines
(A) Due to self-lubricating property
(B) Lesser weight
(C) Lesser size
(D) None of these

What will be the change in emf induced in a de generator if flux is reduced by 20% and
speed is increased by 20% ?

(A) 8% reduced (B) 4% increased

(C) 8% increased (D) 4% reduced

A de motor connected to 220 V supply takes 60 A. The power developed in the armature
is maximum when the back emf 15 ۷
(^) 0 (B) 110
(C) 55 டு) 440
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