Electricity and Circuits: Science for School Students

Electricity and Circuits for ICSE, CBSE and other board school students.

Q. Define an electric current.
Ans: Electric current is the flow of charges.

Q. Why do bulbs have two terminals ?
Ans: The bulb glows when there is a flow of charge. The flow will be present when charges go in and come out as the charges cannot stay inside the bulb. Thus two terminals are present, One for inlet and the other forl outlet.

Q. What are conductors?
Ans: The materials that allow electric current to pass through them are called conductors

Q. What is a battery?
Ans: Battery is made up of two or more cells joined together.

Q. What energy is converted to electrical energy in an electric cell?
Ans: Batteries transform chemical energy into electrical energy.

Q. What are insulators?
Ans: Materials which do not allow electric current to pass through them are called insulators.

Q. Name any two good conductors of electricity.
Ans: Copper and silver are two good conductors of electricity.

Q. What is an electrical circuit?
Ans: An electric circuit is a closed path through which electric current flows from one end to the other.

Q. What do you mean by open and close circuits?
Ans: Electricity Only travels around a circuit that is complete or closed. The electric current will not flow into the circuit which is broken. Such circuits are known as open circuits.

Q. What is an electrolyte? Give an example.
Ans: A liquid that conducts electricity because, of the presence of the irons is called an electrolyte. Example- a solution of copper sulphate salt in water.

Q. Which part of the bulb lights up?
Ans: Filament part of the bulb light up when electricity is passed through a cell.

Q. What happens to a battery If you use it in a circuit for a long time?
Ans: A battery must be discharged if you use it in a circuit from a long time.

Q. Why do you need a switch in a circuit?
Ans: The purpose of a switch in a series circuit is to make it easy to open or close the electrical circuit turning the flow of electricity on or off.

Q. Why does a fused bulb not light up?
Ans: A fused bulb does not light up because, no current passes through its filament

Q. List 3 precautions you should take to protect yourself from the hazards of electric currents.
Ans: There are three precautions-
(a) Avoid water at all times when working with electricity.
(b) Always use insulated tools while working.
(c) Never use equipment with frayed cords, damaged insulation or broken plugs.

Q. Explain why does a bulb light up when it is switched on.
Ans: The current passes through the filament of the bulb and causes the filament to heat up.This causes the filament to glow.

Q. Write down three good reasons why a bulb might not work when you fit it into a circuit.
Ans: Three good reasons are –
(a) The wires are not connected with bulb holder properly.
(b) The switch is not turned on.
(c) The electricity source is not providing any kind of electricity.

Q. Why is an electrical cable made of both metal and plastic?
Ans: The purpose of insulation covering the metal part of an electrical wire is to prevent accidental contact with other conduction of electricity, which might result in an unintentional electric current through those other conduction.

Q. How can you make a simple switch?
Ans: You will need for make a simple switch are-
(a) Small piece of wood or cardboard two metal thumbtacks large metal Paperclip.
(b) Three pieces of wire.
(c) Bulb and bulb holder.
(d) Battery holder.

Q. Write a short note on the electric cell.
Ans: An electrical cell is an electrical power supply. It converts stored chemical energy into electrical potential energy, allowing a current to flow from the Positive terminal to the negative one via an external circuit.

Q. Which of the following arrangement A,B,C and D given bellow should not be set up? Explain ,why.
Ans: Arrangement A should not be set up because, in this arrangement cell will be used up very rapidly as no appliance is connected between the two terminals of the cell.

Q. Why should an electrician use a screw driver with a plastic or wooden handle while carrying out repairs?
Ans: The handles of the tools like screwdriver & plier used by electrician 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.

Q. Describe a simple experiment to test whether a given material is a conductor or an insulator.
Ans: Touch the open ends of the two wires to each other to form a circuit and test the bulb. Touch the two open ends of the wire to each material you are testing, one at a time if the bulb lights up, it is a good conductor Otherwise insulator.

Q. A torch is not functioning Though contact points in the torch are in working condition. What can be the possible reasons for this? Mention any three.
Ans: The possible reasons for not functioning of torch are-
(I) The torch bulb may be fused.
(II) The cells may be discharged.
(III) The connecting wires may be broken up.

Q. What does an electric circuit consist of? Draw an electric circuit and explain its working.
Ans: An electric circuit includes a device that gives energy to the charged Particles constituting the current, such as a battery or a generator, devices that use current, such as lamps, electric Motors or computers, and the. Connecting wires or transmission lines. Note: Draw the electric circuit diagram.

Q. Mr Jalo. has a cell and a single piece of connecting wire. Without cutting the wire in two, Will he be able to make the bulb glow? Explain with the help of a circuit diagram.
Ans: Yes, using the arrangement given below he can succeed in getting the bulb glow. Note: Draw a circuit diagram.

Q. A torch requires three cells, show the arrangement of the cells with a diagram inside the torch that the bulb glows.
Ans: Diagram

Q. Make drawing of what you need to make a bulb light up.
Ans: Drawing

Q. Make a drawing of the correct way to connect two cells.
Ans: Drawing

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