Gen Studies (Electricity and Magnetism)

Assertion is correct. Insulators do not allow the flow of current through themselves. Therefore, insulating materials are advised to use to avoid power shock.
Reason is correct. Insulators do not have free charge carriers. Insulating material reduces or prevents the transmission of heat or sound or electricity.

Statement (1) is wrong. Ammeter is an instrument used to measure the electric current.

Conductivity is the reciprocal of resistance. The resistance of superconductors is zero at low temperatures. So, the conductivity of a superconductor is infinite.

Statement (i) is wrong. In three pin switch, the pin of earth wire is made bigger in size for the security reason.
Statement (ii) is correct. Yes, to reduce the risk of loss of energy, electricity transmitted along power lines is at very high voltages.

(i) Statement (1) is wrong. The 5 star power saving label contains the information regarding electrical consumption, type of equipment, capacitance, etc.
(ii) Statement (2) is also correct. Power rating is made mandatory for frost free refrigerator, air conditioner, tubular fluorescent lamp and distribution transformer.

Statement (1) is wrong. Live wires carry current and our main purpose of using fuse is to break the circuit. A short circuit fault to earth or ground will bypass the neutral wire so, if the fuse were to be installed in the neutral wire, it would not operate.

Statement (2) is also wrong. A fuse is a device which is placed into an electrical circuit to prevent excessive current flowing under fault conditions. The fuse wires should have low melting point because on overloading, the wire forming the fuse element will heat up and melt (or blow) and interrupt the current flow thus preventing damage from excessive current to the remaining circuits.

Statement (1) is correct. Electromagnets are like normal magnets. The electromagnet's strength can be increased or decreased by changing the amount of electric current that flows through the magnet. Therefore, they are used in manufacturing of electric bells and loudspeakers.
Statement (2) is wrong. If a man moves constantly in the direction towards which his magnetic needle points, he would reach North Pole as a freely suspended needle always points in the north direction.

Passengers inside a steel-bodied car are protected from lightning because the car behaves like a 'Faraday Cage'. When the lightning hits the car, it wants to take the shortest path with the least resistance to ground.

Statement (1) is wrong. Iron becomes magnetised and develops the opposite pole and acts as a magnet.
Statement (2) is correct. Alnico is an alloy, which consists of elements like aluminium, nickel, cobalt, copper, Iron and some other elements, which have one of the magnetic characteristics. Moreover, Alnico with these constitute elements is preferred to make magnets.

Statement (1) is wrong. The purpose of choke in tube light is to increase the voltage momentarily.
Statement (2) is correct. Lightening in the sky is caused due to electric discharge produced by friction between clouds.

Statement (1) is wrong. The heating of a current carrying conductor is caused due to loss of kinetic energy by electrons.
Statement (2) is wrong. Earthing is the method of connecting the metallic body of an electrical appliance to the earth with the help of a conducting wire.

By rubbing the rubber ruler, it acquires the negative charge. When it comes in contact with tiny piece of paper (having no charge), it induces the opposite positive charge.

The magnetic imprint on the tape induces a small current in the head, which approximates the original signal and is then amplified for playback.

Statement (1) is incorrect. When a bar magnet is cut into two equal halves, the pole strength of each piece remains the same. Each broken piece forms its own magnetic field.
Statement (2) is correct. Retentivity is the capacity of a body to remain magnetized after magnetizing field has ceased to exert an effect.