The switch is initially open in the following circuit as sho

The switch is initially open in the following circuit as shown. When the switch is closed, is the circuit in the resistor directed left or right? In part above which terminal of the resistor is positive, a or b? A bar magnet moves towards a coil as shown. Which terminal of the resistor is positive, a or b? A wire loop in a magnetic field as shown. The direction of B is indicated as the magnitude B is changing. If terminal \"a\" of the resistor is positive with respect to terminal \"b\", is the magnitude increasing or decreasing?

Solution

(a).When switch is closed,magnetic field is developed in the along the axial line of the circular wire.So, induced emf deveoped in the secondary coil such that it opposes the magnetic field.Therefore the induced current is along left direction.

(c).Terminal b is positive.

(b). When a bar magnet moves towards the coil then induced current is developed in the coil such that it opposes the motion of the bar magnet.i.e., counter clock wise direction.

Therefore terminal \"a \" is positive.

(e).decreasing