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(a) What is the function of an earth wire in electrical instruments? Why is it necessary to earth the metallic electric appliances?
(b) Explain what is short-circuiting and overloading in an electric supply.
(c) What is the usual capacity of the fuse wire in the line to feed:
(i) Lights and fans?
(ii) Appliances of 2 kW or more power?
The diagram below shows a coil connected to a centre zero galvanometer G. The galvanometer shows a deflection to the right when the N-pole of a powerful magnet is moved to the right as shown.
(i) Explain why the deflection occurs in the galvanometer.
(ii) Does the direction of current in the coil appear clockwise or anticlockwise when viewed from end A?
(iii) State the observation in G when the coil is moved away from N.
(iv) State the observation in G when, both coil and the magnet, are moved to the right at the same speed.
The figure shows a long solenoid, a cylindrical coil of a number of turns of insulated copper wire, connected to a battery through an ammeter A and a rheostat Rh.
(i) Which end of the solenoid is an N-pole and which end is an S-pole?
(ii) Draw the magnetic field lines inside the solenoid and indicate their directions. Are magnetic field lines closed?
(iii) How can you increase the strength of the magnetic field inside the solenoid? Give two methods.
(a) What is meant by a magnetic field?
(b) How is the direction of magnetic field at a point determined?
(c) Describe an activity to demonstrate the direction of the magnetic field generated around a current carrying conductor.
(d) What is the direction of magnetic field at the centre of a current carrying circular loop?