A very long solenoid with its axis perpendicular to the page generates an inward magnetic field whose magnitude increases with time. This induces an emf in a conducting wire loop around the solenoid which lights two identical bulbs `A` and `B` connected in series along the wire. Now two points dimetrically opposite on the wire loop are shorted with another conducting wire (having zero resistance) lying to the right og bulb `B` in the plane of the page. After the shorting wire is inserted:

Options

A. bulb `A` does not glow, and bulb `B` dims.
B. bublb `A` does not glow, and bulb `B` gets brighter.
C. bulb `B` does not glow, and bulb `A` dims.
D. bulb `B` does not glowm, and bulb `A` goes brighter.

Answer

D

Explanation

If the source of induced emf is represented by equivalent cell, the circuit equivalent is shown as.
Hence after shorting wire. Bulb `B` will not glow as potential difference across it is zero. Since the complete current through bulb A will now pass through shorting wire (zero resistance) the effective resistance shall decrease and bulb A gets brighter.