Class Notes NCERT Solutions for CBSE Students
Question: What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Answer: Electric switch is used to make electric circuit open or closed for a particular appliance and hence with the help of a switch we can use an appliance according
Question: Would the bulb glow after completing the circuit shown in Fig. 12.9 if instead of safety pin we use an eraser?
Answer: No, since eraser is an insulator so it does not allow the current to pass. Hence the bulb will not glow.
Question: 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.
Answer: Yes, if the object is good conductor of electricity then current will pass through conduction tester and the bulb will glow. Hence the object will be a conductor of electricity.
Question: Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Answer: Our body is good conductor of electricity and rubber is insulator. During repairing work if the body comes in contact with current carrying wire then there will not be any accident as rubber does not allow the passage of current through it. Hence electrician uses rubber gloves while repairing an electric switch.
Question: The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?
Answer: Plastic or rubber is an insulator which does not allow electric current to pass through it. The handles of the tools like screwdrivers and pliers used by electricians for repair have covering of plastic or rubber so that electric current may not pass through these tools to the body of the electrician to harm him.
It was really very helpful to me.