A portable radio has a built-in transformer so that it can work from the mains instead of batteries. Is this a step-up or step down transformer?

The wire in Figure below is being moved downwards through the magnetic field so as to produce induced current.

What would be the effect of:

(a) moving the wire at a higher speed?

(b) moving the wire upwards rather than downwards?

(c) using a stronger magnet?

(d) holding the wire still in the magnetic field?

(e) moving the wire parallel to the magnetic field lines?

Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:

(i) a current is passed through coil B by plugging the key?

(ii) the current is stopped by removing the plug from the key?

What name is given to the device which automatically cuts off the electricity supply during short-circuiting in household wiring?

What is the usual capacity of an electric fuse used (i) in the lighting circuit, and (ii) in the power circuit, of a small house?