HARD
Physics
IMPORTANT
Earn 100
As a result of the change in the magnetic flux linked to the closed loop, shown in the figure, an emf of is induced in the loop. The work done (in ) in taking a charge of once along the loop is
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Important Questions on Electromagnetic Induction and Alternating Currents
HARD
Physics
IMPORTANT
The magnetic field within a cylindrical region, whose cross-section is as indicated, starts increasing at a constant rate of . The graph showing the variation of induced field with distance from the axis of cylinder is:
HARD
Physics
IMPORTANT
A thin non-conducting ring of mass and radius carrying a charge can rotate freely about its own axis which is vertical. At the initial moment the ring was at rest in horizontal position and no magnetic field was present. At instant , a uniform magnetic field is switched on which is vertically downward and increases with time according to the law . Neglecting magnetism induced due to rotational motion of ring.The magnitude of the electric field on the surface of the ring is:
MEDIUM
Physics
IMPORTANT
A uniform but time varying magnetic field exists in cylindrical region and directed into the paper. If field decreases with time and a positive charge is placed at any point inside the region, then it moves
EASY
Physics
IMPORTANT
The magnetic flux through each turn of a turn coil is , where is in second. The induced emf at is
HARD
Physics
IMPORTANT
A self-induced emf in a solenoid of inductance changes in time as . Assuming the charge is finite, find the total charge that passes a point in the wire of the solenoid.
HARD
Physics
IMPORTANT
A transformer with efficiency works at and . If the secondary voltage is then the primary and secondary currents are respectively
HARD
Physics
IMPORTANT
Two coils have a mutual inductance The current changes in the first coil according to equation where and The maximum value of emf in the second coil is
HARD
Physics
IMPORTANT
In the adjacent circuit, the instantaneous current equation is
