Plastics and rubbers are the bad conductor of electricity. So, handle of tools such as screwdrivers, pliers, etc. which are used by electricians to repair electrical appliances usually have plastic or rubber cover on them.
An electric switch conducts electricity through its internal parts and one may get an electric shock if it is touched with naked hands. Hence, it should be touched with rubber gloves in hand because rubber cannot conduct electricity.
The bulb of the conduction tester glows when the tester is touched with the object. It shows that the given object conducts electricity. Hence, the object is a conductor in nature.
No. The bulb will not glow because the two terminals of the cell are connected to the single terminal of the bulb. In order to complete the circuit, the two terminals of the cell should be connected to the two terminals of the bulb.
No. The bulb will not glow if we connect an eraser in the circuit. It is because erasers are bad conductor of electricity. They do not conduct electricity. The circuit becomes an open circuit.
In the given circuit, a tester holder is connected in series. Electric current cannot pass through tester holders because it is a bad conductor of electricity. Hence, the current will not flow through the circuit and hence, the bulb will not glow.
(a) A device that is used to break an electric circuit is called a switch.
(b) An electric cell has two terminals.
A switch is used to complete or break an electric circuit. If the switch is ‘ON’, then current will flow through the circuit. On the other hand, if the switch is ‘OFF’, then current will not flow through the circuit. Electric fans, electric lamps, washing machines, juicers and mixers, etc. have switches built into them.
In order to complete the circuit, the positive terminal of the cell should be connected to one end of the bulb, and the other terminal of the bulb should be connected to the other end of the bulb. It can be shown in the figure.
(a) Electric current can flow through metals. (True)
Explanation: Electric current can pass through metals as they allow an electric current to flow through them easily.
(b) Instead of metal wires, a jute string can be used to make a circuit. (False)
Explanation: Jute string is an insulator. Hence, electric current cannot pass through it.
(c) Electric current can pass through a sheet of thermo Col. (False)
Explanation: Thermo Col is also an insulator. Hence, electric current cannot pass through it.
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