Draw a labelled diagram of a device you would use to transform 220 V a.c. to 15 V a.c. Name the device and explain how does it work. Give it's two uses.

The diagram below shows a magnetic needle kept just below the conductor AB which is kept in North South direction.

(i) In which direction does the needle deflect when the key is closed ?

(ii) Why is the deflection produced?

(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?

(iv) Name one device which works on this principle.

Draw a labelled diagram of a step up transformer and explain how does it work. State two characteristics of the primary coil as compared to it's secondary coil.

The diagram in figure shows the core of a transformer and it's input and output connections.

(a) State the material used for the core and describe it's structure.

(b) Complete the diagram of the transformer and connections by labelling all parts joined by you.

(c) Name the transformer : step up or step down.