Electricity and Circuits

  

Chapter 12              Electricity and Circuits

ELECTRICITY AND CIRCUITS

Electricity is a form of energy that is generated by the movement of electrons. It is used to power many everyday items, from lights and appliances to computers and cars. The electricity we use today comes in two forms: direct current (DC) and alternating current (AC). DC electricity flows in one direction, while AC electricity alternates directions.

Electricity can be generated from a variety of sources, including hydropower, thermal power, wind power, solar power, and nuclear power. Each type of energy source has its own advantages and disadvantages when it comes to generating electricity.

Electric cell

Electric cell is a device that converts chemical energy into electrical energy. It consists of two terminals, an anode and a cathode, which are connected by an electrolyte. When the terminals are connected to a circuit, electricity flows through it due to the movement of electrons from the anode to the cathode. This process is known as a chemical reaction and it produces electric current and charge. Electric cells are used in many applications such as batteries, fuel cells, solar cells and more.

Circuit

Circuit is a closed path in which electricity can flow from the source to the terminal. It consists of wires, switches, fuses, and plugs that are connected together to form a complete loop. The electricity flows through the circuit when it is switched on and off by the switch. The fuse protects the circuit from overloads and short circuits while the plug provides an easy way to connect and disconnect devices from the circuit.

Electric switch

An electric switch is a device that is used to make or break an electrical circuit. It is designed to protect the circuit from overloads and short circuits. 

Fuse

A fuse is a type of safety device that uses a thin wire or strip of metal to break the circuit when it becomes overloaded. Fuses are used in many electrical systems, such as home appliances, automobiles, and industrial machinery. They are essential for ensuring the safety of both people and equipment.

Conductors and insulators 

Conductors and insulators are materials that have different electrical properties. Conductors allow electricity to flow through them easily eg iron copper gold silver etc,This means that conductors can be used to carry electrical current,  while insulators resist the flow of electricity, ie they does not allow  electricity to flow through them easily eg straw grass plastic etc. Insulators can be used to protect people from electric shock. Understanding the differences between conductors and insulators is important for anyone working with electricity or electronics.

Solved Textbook Questions

 

ELECTRICITY AND CIRCUITS

Q1. Fill in the blanks:

(a) A device that is used to break an electric circuit is called______________.

Ans: Switch

(b) An electric cell has__________.

Ans: Two

Q2. Mark ‘True’ or ‘False’ for the following statements:

(a) Electric current can flow through metals. True

(b) Instead of metal wires, a jute string can be used to make a circuit. 

© Electric current can pass through a sheet of thermocol. 

Ans: a. True. b. False.  c. False

Q3. .Explain why the bulb would not glow in the arrangement shown in fig

Ans: The bulb would not glow in the arrangement shown in figure because the one end of tester/screw driver is made up of insulator(plastic) which does not allow the electric current to flow through it.

Q4.Complete the drawing shown in Fig. 12.9 to indicate where the free ends of the two wires should be joined to make the bulb glow.

Ans:

Q5.What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Ans: 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

 

Q6. Would the bulb glow after completing the circuit shown in Fig. 12.9 if instead of safety pin we use an eraser?

Ans: No, since eraser is an insulator so it does not allow the current to pass. Hence the bulb will not glow.

Q7.Would the bulb glow in the circuit shown in Fig. 12.11.

Ans: Yes, the electric circuit is closed so the bulb will 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.
Ans: 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.

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

 

1