Electricity and Circuits
KEYWORDS
• Electric circuit: the closed path of flow of electric current
• Filament: a piece of tungsten wire inside a bulb which glows when an electric current passes through it
• Switch: a device that closes or opens a circuit by allowing or preventing flow of current
• Conductors: the materials that allow the flow of electric current through them
• Insulators: the materials that do not allow the flow of electric current through them
• Battery: a combination of two or more cells is called Battery.
• Open circuit: the circuit in which no current flows. It is also known as incomplete circuit
•Closed circuit: the circuit in which the current flows: It is also known as complete circuit
• Bulb: a device which converts electrical energy into light energy
POINTS TO REMEMBER
• We get electrical energy to run electrical devices from the mains or from cells.
• A group of connected cells forms a battery.
• The path along which a current can flow is called a circuit. A circuit can be opened or closed with the help of a switch.
• Materials that conduct electricity well are called conductors.
• Materials that do not conduct electricity are called insulators.
• Electric cell is a source of electricity.
• The switch is a simple device that is used either to break the electric circuit or to complete it.
• A cell is a source of electrical energy.
• A cell has two terminals, a positive and a negative terminal.
• Electricity plays a vital role in our daily life.
• Precautions against hazards of electric current must be taken.
• Cells that are used in calculators, wrist watches, etc. are very compact and are called button cells.
Multiple-choice Questions:
1. Which of the following is not a conductor?
(a) Copper
(b) Mica
(c) Silver
(d) Iron
2. Which of the following is an insulator?
(a) Silver
(b) Aluminum
(c) Copper
(d) Plastic
3. Where do we get electricity from a
(a) sun
(b) metal
(c) wire
(d) battery
4. Electric current flows only when the circuit is
(a) open
(b) closed
(c) incomplete
(d) broken
5. The energy provided by electricity is called
(a) electrical energy
(b) chemical energy
(c) solar energy
(d) all of these
6. The flow of electricity is known as electric
(a) energy
(b) power
(c) generator
(d) current
7. Which of these does not use electricity?
(a) Gas stove
(b) Computer
(c) Television
(d) Steam Iron
8. In an electric circuit, the bulb will glow when the circuit is
(a) open
(b) closed
(c) both (a) and (b)
(d) neither when open nor when closed
9. How many terminals are there in a dry cell?
(a) One
(b) Two
(c) Three
(d) Four
10. A bulb whose filament is broken is called
(a) conductor
(b) glowing
(c) open up
(d) fused
Ans:
1. (b) 2. (b) 3. (d) 4. (b) 5. (a) 6. (b) 7. (a) 8. (b) 9. (b) 10. (d)
Fill in the blanks:
1. Electricity is the basic part of nature and is one of the most widely used forms of————-.
2. A large number of machines in shops and factories run on—————–.
3.————-is an electrical component used for lighting.
4. A switch is a device which controls the ON-OFF mechanism of any electric———–.
Ans:
1. Electricity is the basic part of nature and is one of the most widely used forms of energy.
2. A large number of machines in shops and factories run on electricity.
3. The bulb is an electrical component used for lighting.
4. A switch is a device which controls the ON-OFF mechanism of an electric circuit.
State whether ‘True’ or ‘False’
1. Plastic is an insulator.
2. The electric circuit allows current to flow through.
3. The electric cell has one terminal only.
4. A bulb gives light when its filament glows.
5. A battery consists of two or more cells.
Ans:
1. True, 2. True, 3. False, 4. True, 5. True
CLASS VI SCIENCE