NCERT Class 6th Science Chapter 9 Electricity and Circuits Question Answers

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NCERT Class 6th Science Chapter 9 Electricity and Circuits Question Answers

1. Fill in the blanks:

(a) A device that is used to break an electric circuit is called a switch.
(b) An electric cell has two terminals.

2. Mark 'True' or 'False' for the following statements:

(a) Electric current can flow through metals.
True. Metals are good conductors of electricity, allowing electric current to pass through them easily.

(b) Instead of metal wires, a jute string can be used to make a circuit.
False. Jute string is an insulator and does not allow electric current to flow through it.

(c) Electric current can pass through a sheet of thermo Col.
False. Thermo Col is an insulator and does not allow electric current to pass through it.

3. Explain why the bulb would not glow in the arrangement shown in Fig. 9.13.

Ans.

        The bulb will not light since the circuit is broken due to the insulator in the middle.

4. Complete the drawing shown in Fig. 9.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Ans.

         

5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Ans.

Purpose of an Electric Switch:
An electric switch is used to control the flow of electricity in a circuit. It can either complete the circuit (switching it on) or break the circuit (switching it off). By using a switch, we can easily turn electrical devices on or off as needed.

Examples of Electrical Gadgets with Built-in Switches:

• Electric lamp: A switch is used to turn the lamp on or off.
• Television: A switch (or button) is used to turn the TV on or off.
• Fan: A switch is used to control the operation of a ceiling or table fan.
• Electric Iron: A switch is used to turn the iron on or off.

6. Would the bulb glow after completing the circuit shown in Fig. 9.14 if instead of a safety pin we use an eraser?

Ans.

No, the bulb would not glow if an eraser is used instead of a safety pin. This is because the eraser is an insulator, which means it does not allow electric current to pass through it. To complete the circuit and make the bulb glow, a conductor (such as a safety pin or metal wire) must be used to allow the current to flow.

7. Would the bulb glow in the circuit shown in Fig. 9.15?

Ans.

        No, the bulb will not glow.

8. Using the "conduction tester" on an object, it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.

If the bulb begins to glow when using the "conduction tester" on an object, the object is a conductor. This is because conductors allow electric current to pass through them, completing the circuit and causing the bulb to light up. Insulators, on the other hand, do not allow current to pass, so the bulb would not glow if an insulator was tested.

9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

An electrician should use rubber gloves while repairing an electric switch because rubber is an insulator. As an insulator, rubber does not allow electric current to pass through it. This protects the electrician from the risk of electric shock, which can occur if they accidentally come into contact with live wires or other conducting materials. By wearing rubber gloves, the electrician ensures that they are insulated from the electricity and reduces the danger of injury.

10. The handles of tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

The handles of tools like screwdrivers and pliers used by electricians are covered with plastic or rubber because these materials are insulators. Insulators do not conduct electricity, so by covering the handles with insulating materials, the electrician is protected from electric shocks. If the metal parts of the tools were to come into contact with live wires, the insulating handle would prevent the electric current from passing through the electrician's body, ensuring their safety while working.