The chapter Electricity: Magnetic and Heating Effects deals with the magnetic and heating effects of electric current in a simple way. In this chapter students are going to learn about electromagnets, electric cells, dry cells, and rechargeable batteries work in daily life.
This set of MCQs and match-the-following questions focuses on the key concepts of the chapter. The questions are simple, interactive, and will give an easy revision for students.
MCQ for Class 8 Science MCQ Questions and Answers.
Electricity: Magnetic and Heating Effects Class 8 Science Chapter 4 MCQ Online Test Questions and Answers
Question 1. When electric current flows through a conductor like a wire, it produces:
a) Only heat
b) Only light
c) A magnetic field around it
d) A chemical change in air
Answer:
c) A magnetic field around it
Question 2. In Oersted’s observation, the magnetic compass needle got deflected when:
a) The wire was cooled
b) Current flowed through the wire
c) The battery was removed completely
d) The compass was kept very far away
Answer:
b) Current flowed through the wire
Question 3. The deflection of a compass needle placed near a current-carrying wire shows that the wire has:
a) Mass
b) Volume
c) Magnetic effect
d) Elasticity
Answer:
c) Magnetic effect
Question 4. The region around a magnet or a current-carrying wire where its effect can be felt is called the:
a) Electric zone
b) Magnetic field
c) Power source
d) Resistance region
Answer:
b) Magnetic field
Question 5. When the current through a wire stops, the magnetic field around it:
a) Becomes stronger
b) Changes into heat
c) Disappears
d) Turns into light
Answer:
c) Disappears
Question 6. The scientist who discovered the link between electricity and magnetism in 1820 was:
a) Newton
b) Hans Christian Oersted
c) Faraday
d) Edison
Answer:
b) Hans Christian Oersted
Question 7. Which of the following devices works on the magnetic effect of electric current?
a) Electric bell
b) Loudspeaker
c) Motor
d) All of these
Answer:
d) All of these
Question 8. A coil of insulated wire carrying current behaves like a:
a) Heater
b) Magnet
c) Resistor only
d) Fuse only
Answer:
b) Magnet
Question 9. A current-carrying coil that behaves as a magnet is called an:
a) Electrolyte
b) Electrode
c) Electromagnet
d) Insulator
Answer:
c) Electromagnet
Question 10. An iron core is inserted inside an electromagnet mainly to:
a) Reduce the current to zero
b) Make the magnet stronger
c) Stop heat generation completely
d) Change copper into iron
Answer:
b) Make the magnet stronger
Question 11. When current is switched off in an electromagnet, it:
a) Remains permanently magnetised
b) Loses its magnetic effect
c) Becomes a battery
d) Starts producing light
Answer:
b) Loses its magnetic effect
Question 12. In a simple electromagnet, the objects most easily attracted to the iron core are:
a) Plastic clips
b) Wooden sticks
c) Iron paper clips
d) Rubber bands
Answer:
c) Iron paper clips
Question 13. Like a bar magnet, an electromagnet also has:
a) Only one pole
b) Three poles
c) Two poles
d) No poles
Answer:
c) Two poles
Question 14. If the north pole of a compass is attracted towards one end of an electromagnet, that end of the electromagnet is its:
a) North pole
b) South pole
c) Neutral point
d) Centre only
Answer:
b) South pole
Question 15. The strength of an electromagnet can be increased by:
a) Decreasing the number of turns of the coil
b) Using fewer cells
c) Increasing the number of turns of the coil
d) Removing the wire completely
Answer:
c) Increasing the number of turns of the coil
Question 16. Compared to a single cell, a battery with more cells generally makes an electromagnet:
a) Weaker
b) Stronger
c) Non-magnetic
d) Hotter but never magnetic
Answer:
b) Stronger
Question 17. The poles of an electromagnet can be reversed by:
a) Increasing the wire length only
b) Changing the direction of current
c) Using a thicker nail
d) Keeping the switch open
Answer:
b) Changing the direction of current
Question 18. Lifting electromagnets are useful in factories and scrap yards because they can:
a) Lift and release metal objects by switching current ON and OFF
b) Attract all materials equally
c) Work without electricity
d) Separate wood from plastic
Answer:
a) Lift and release metal objects by switching current ON and OFF
Question 19. A current-carrying wire gets heated because electric current faces some opposition called:
a) Reflection
b) Resistance
c) Refraction
d) Radiation
Answer:
b) Resistance
Question 20. A nichrome wire is used in heating experiments because, compared to copper of the same size, nichrome has:
a) Lower resistance
b) Higher resistance
c) No resistance
d) Infinite resistance so current cannot pass
Answer:
b) Higher resistance
Question 21. The warming of a conductor when current passes through it is known as the:
a) Magnetic effect of current
b) Chemical effect of current
c) Heating effect of current
d) Solar effect of current
Answer:
c) Heating effect of current
Question 22. If the same nichrome wire is connected to a battery of 2 cells instead of 1 cell for the same time, the wire generally heats up:
a) Less
b) More
c) Not at all
d) Exactly the same in every case
Answer:
b) More
Question 23. The amount of heat generated in a wire depends on the:
a) Material, thickness, length, and duration of current flow
b) Colour of the wire only
c) Shape of the cell only
d) Size of the switch only
Answer:
a) Material, thickness, length, and duration of current flow
Question 24. Which part of an electric heater, iron, or kettle gets hot due to current and produces heat?
a) Plastic casing
b) Heating element
c) Switch cover
d) Plug pin coating
Answer:
b) Heating element
Question 25. One danger of the heating effect of electric current in household wiring is that it may:
a) Increase magnetism of plastic
b) Melt plastic parts of plugs and sockets
c) Turn copper into steel
d) Stop all current permanently
Answer:
b) Melt plastic parts of plugs and sockets
Question 26. A Voltaic cell generates electricity because of:
a) Friction between wires
b) Chemical reactions inside it
c) Heat from the Sun
d) Only the shape of the container
Answer:
b) Chemical reactions inside it
Question 27. A simple Voltaic cell contains two different metal plates and a liquid called:
a) Coolant
b) Lubricant
c) Electrolyte
d) Filament
Answer:
c) Electrolyte
Question 28. In a Voltaic cell, the metal plates dipped in the electrolyte are called:
a) Electromagnets
b) Electrodes
c) Conductors only
d) Filaments
Answer:
b) Electrodes
Question 29. A Voltaic cell stops working after some time mainly because:
a) The glass container melts
b) The wires become magnetic
c) The chemicals get used up
d) The air around it disappears
Answer:
c) The chemicals get used up
Question 30. In a lemon cell, the electrolyte is:
a) Pure water
b) Lemon juice
c) Carbon rod
d) Copper strip
Answer:
b) Lemon juice
Question 31. In a dry cell, the electrolyte is not a liquid but a:
a) Gas
b) Thick moist paste
c) Metal sheet
d) Solid iron rod
Answer:
b) Thick moist paste
Question 32. In a dry cell, the zinc container acts as the:
a) Positive terminal
b) Negative terminal
c) Electrolyte
d) Insulating layer
Answer:
b) Negative terminal
Question 33. In a dry cell, the carbon rod with the metal cap acts as the:
a) Negative terminal
b) Heating element
c) Positive terminal
d) Outer container
Answer:
c) Positive terminal
Question 34. Rechargeable batteries are preferred in many applications because they can be:
a) Broken and remade easily
b) Recharged and reused multiple times
c) Used without any chemical reaction
d) Permanently used without wearing out
Answer:
b) Recharged and reused multiple times
Question 35 – Match the Following
| Column A | Column B |
|---|---|
| 1. Magnetic effect of electric current | A. Current-carrying wire gets warm |
| 2. Electromagnet | B. Coil behaves like a magnet |
| 3. Heating effect of electric current | C. Produces magnetic field around a wire |
| 4. Nichrome wire | D. Used in heating devices |
| 5. Lifting electromagnet | E. Used to lift and release heavy metal objects |
Answer:
| Column A | Correct Answer |
|---|---|
| 1. Magnetic effect of electric current | C. Produces magnetic field around a wire |
| 2. Electromagnet | B. Coil behaves like a magnet |
| 3. Heating effect of electric current | A. Current-carrying wire gets warm |
| 4. Nichrome wire | D. Used in heating devices |
| 5. Lifting electromagnet | E. Used to lift and release heavy metal objects |
Question 36 – Match the Following
| Column A | Column B |
|---|---|
| 1. Voltaic cell | A. Can be recharged and reused |
| 2. Electrolyte | B. Thick moist paste in dry cell or liquid in Voltaic cell |
| 3. Zinc container in dry cell | C. Negative terminal |
| 4. Carbon rod with metal cap | D. Positive terminal |
| 5. Rechargeable battery | E. Generates electricity by chemical reaction |
Answer:
| Column A | Correct Answer |
|---|---|
| 1. Voltaic cell | E. Generates electricity by chemical reaction |
| 2. Electrolyte | B. Thick moist paste in dry cell or liquid in Voltaic cell |
| 3. Zinc container in dry cell | C. Negative terminal |
| 4. Carbon rod with metal cap | D. Positive terminal |
| 5. Rechargeable battery | A. Can be recharged and reused |
