The ICSE Selina Class 8 Physics Chapter 8 – Electricity deals with topics related to electricity, photons and electrons. The solution given by the subject specialists at BYJU’S is up to date and based on the examination point of view. The ICSE Selina Class 8 Physics Chapter 8 – Electricity Solutions are accurate and precise helping you to compare your answers with it quickly. The Selina questions cover all the topics in the chapters, with proper reference of different books to find the solutions from the vast chapter. BYJU’S makes it easy for you by providing the best answer handy.
Electricity is nothing but a form of energy produced by charges. These charges that produce electricity can be at rest or moving. In this chapter, ICSE Class 8 chapter 8 for Physics, Electricity, we learn how these moving charges constitute the electricity. The flow of free electrons or charger in a particular direction frames an electric current or current electricity. Electric current is defined as the charge flowing per unit time through a conductor.
Current = charge/time
I = q / t
A. Objective Questions
1. Write true or false for each statement:
(a) A fuse wire has a high melting point.
(b) The flow of protons constitutes the electric current.
(c) Silver is an insulator of electricity.
(d) S.L. unit and commercial unit of electrical energy are the same.
(e) Overloading of electric current in circuits can lead to short-circuiting.
(f) Our body can pass electricity through it.
(g) All metals are insulators of electricity.
(h) The earth wire protects us from an electric shock.
(i) A switch should not be touched with wet hands.
(j) AH electrical appliances in a household circuit work at the same voltage.
(k) In a cable, the green wire is the live wire.
(l) A fuse is connected to the live wire.
(m) A switch is connected to the neutral wire.
Fill in the blanks
(a) The unit in which we pay the cost of electricity is kWh.
(b) The electrical energy consumed in a house is measured by kWh meter.
(c) In a household electrical circuit, the appliances are connected in parallel with the mains.
(d) A switch is connected to the live wire.
(e) The red colour insulated wire in a cable is the live wire.
(f) One kilowatt hour is equal to 3.6×106 joule.
(g) A fuse wire should have a low melting point.
Match the following
Column A Column B
(a) Electric power (i) volt
(b) kWh (ii) joule
(c) Electric current (iii) volt × ampere
(d) Electric energy (iv) watt
(e) watt (v) ampere
(f) Potential difference (vi) electrical energy
Column A Column B
(a) Electric power (iv) watt
(b) kWh (vi) electrical energy
(c) Electric current (v) ampere
(d) Electric energy (ii) joule
(e) watt (iii) volt × ampere
(f) Potential difference (i) volt
Select the correct alternative
(a) All wires used in electric circuits should be covered with
1. colouring material
2. conducting material
3. an insulating material
4. none of the above
Answer: 3. an insulating material
(b) Electric work done per unit time is
1. electrical energy
2. electric current
3. electric voltage
4. electrical power
Answer: 4. electrical power
(c) One kilowatt is equal to
1. 100 watt
2. 1000 watt
3. 10 watt
4. none of these
Answer: 2. 1000 watt
(d) Fuse wire is an alloy of
Answer: 1. tin-lead
(e) A fuse wire should have
1. a low melting point
2. high melting point
3. very high melting point
4. none of the above
Answer: 1. a low melting point
(f) When the switch of an electric appliance is put off, it disconnects
1. the live wire
2. the neutral wire
3. the earth wire
4. the live and the neutral wire
Answer: 1. the live wire
(g) The purpose of an electric meter in a house is
1. to give the cost of electricity directly
2. to give the consumption of electrical energy
3. to safeguard the circuit from short-circuiting
4. to put on or off the mains.
Answer: 2. to give the consumption of electrical energy
(h) If out of the two lighted bulbs in a room, one bulb suddenly fuses, then
1. other bulb will glow more
2. other bulb will glow more
3. other bulb will also fuse
4. other bulb will remain lighted unaffected.
Answer: 4. other bulb will remain lighted unaffected.