Chapter 14 Chemical Effects of Electric Current mcqs & important question science | class 8th

MCQ Questions for Class 8 Science: Ch 14 Chemical Effects of Electric Current

1. Which of the following does not conduct electricity?

(a) Sugar solution

(b) Vinegar solution

(c) Lemon juice solution

(d) Caustic soda solution

► (a) Sugar solution

2. An electric lamp glows due to        

(a) Chemical effect        

(b) Magnetic effect        

(c) Heating effect        

(d) None

► (c) Heating effect        

3. Battery is a

(a) Large single cell

(b) Combination of two or more cells

(c) Combination of two cell only

(d) Combination of cell and conductor

► (b) Combination of two or more cells

4. Potential difference is created in a electric circuit due to
(a) Switch
(b) Cell or battery
(c) Voltmeter
(d) Conductor
► (b) Cell or battery

5. In electrolytic solutions, which of the following acts as carrier of charge?

(a) Protons

(b) Electrons

(c) Neutrons

(d) Ions

► (d) Ions

6. Fuse wire is used in electric circuit to prevent

(a) Electrical appliances and circuit from high current

(b) Prevent the insulator

(c) Us from electric shock

(d) Prevent the ammeter

► (a) Electrical appliances and circuit from high current

7. Which of the appliances at your home does not run on electric current?

(a) Television

(b) Mixer grinder

(c) Air conditioner

(d) Gas burner

► (d) Gas burner

8. The passage of an electric current through a solution causes

(a) Heating effect

(b) Lighting effect

(c) Chemical effect

(d) All of these

► (c) Chemical effect

9. In a dry cell, which of the following acts as the positive terminal?

(a) Carbon rod

(b) Manganese dioxide

(c) Manganese dioxide and powdered carbon

(d) A metal cap on the carbon rod

► (d) A metal cap on the carbon rod

10. Electroplating is based on:

(a) magnetic effect of electricity

(b) chemical effect of electricity

(c) heating effect of electricity

(d) physical effect of electricity

► (b) chemical effect of electricity

11. Distilled water is

(a) Poor conductor

(b) Good conductor

(c) Both (a) and (b)

(d) None

► (a) Poor conductor

12. A device which prevents or allow the current to flow through it

(a) Conductor

(b) Motor

(c) Terminal

(d) Switch

► (d) Switch

13. What is current?

(a) The flow of matter

(b) The flow of electrons

(c) The flow of protons

(d) The flow of charge

► (d) The flow of charge

14. Electric current is measured by a device

(a) Odometer

(b) Voltmeter

(c) Ammeter

(d) Galvanometer

► (c) Ammeter

15. In battery two or more cells are connected in

(a) Series

(b) Random

(c) Positive and positive terminals

(d) Parallel

► (a) Series

16. Which of the following liquids is a bad conductor of electricity?

(a) Lemon juice

(b) Vinegar

(c) Sea water

(d) Distilled water

► (d) Distilled water

17. Which acid is present in lemon juice that acts as an electrolyte?

(a) Sulphuric acid

(b) Nitric acid

(c) Hydrochloric acid

(d) Citric acid

► (d) Citric acid

18. Which categories of substance are generally good conductors?

(a) Insulator

(b) Non-metals

(c) Metals

(d) Reflector

► (c) Metals

19. An electric lamp glows due to

(a) Chemical effect

(b) Magnetic effect

(c) Heating effect

(d) None

► (c) Heating effect

20. Which metal is electroplated on iron for making “cans” for storing food and drinks?

(a) Chromium metal

(b) Silver metal

(c) Tin metal

(d) Copper metal

► (c) Tin metal

21. Which of the following are the characteristics of an electrolyte?

(a) It has a positive charge.

(b) It has a negative charge.

(c) It conducts charge without dissociating.

(d) It forms positive and negative ions.

► (d) It forms positive and negative ions.

22. What is the common name for manganese-dioxide-alkaline-zinc cell?

(a) Moz cell

(b) Long life cell

(c) Manganese-dioxide

(d) Alkaline cell

► (d) Alkaline cell

23. Which of the following is an insulator?

(a) Wood

(b) Iron

(c) Graphite

(d) Silver

► (a) Wood

24. In electric circuit, current flows due to

(a) Difference in temperature

(b) Same potential difference

(c) Difference in potential difference

(d) Difference in current

► (c) Difference in potential difference

25. The bulb glows when the electric current passes through it due to

(a) Lighting effect of electric current

(b) Magnetic effect of electric current

(c) Heating effect of electric current

(d) Chemical effect of electric current

► (c) Heating effect of electric current

Class 8 Science Chapter 14 Extra Questions and Answers Chemical Effects of Electric Current

Extra Questions for Class 8 Science Chapter 14 Chemical Effects of Electric Current with Answers Solutions

Chemical Effects of Electric Current Class 8 Extra Questions Very Short Answer Type

Question 1.
What are good conductors?
Answer:
The substances that conduct electricity through them are called good conductors.

Question 2.
What are insulators or poor conductors?
Answer:
The substances that do not conduct electricity through them are poor conductors or insulators.

Question 3.
Give four examples of conductors.
Answer:
Copper, iron, aluminium and brass.

Question 4.
Give four examples of insulators.
Answer:
Air, wood, rubber and plastic.

Question 5.
Name two metal objects which have a coating of another metal.
Answer:
Handlebars of bicycles, bathroom taps.

Question 6.
What do we get on electrolysis of acidified water?
Answer:
Hydrogen and oxygen gas.

Question 7.
Is air a bad or good conductor?
Answer:
A bad conductor.

Question 8.
Which metal is plated on handle bars of cycles and rim of wheels?
Answer:
Chromium

Question 9.
What is the full form of LED?
Answer:
Light Emitting Diode.

Question 10.
How do we check the electric current?
Answer:
We check the electric current by using a tester.

Question 11.
Which part of an atom is responsible for flow of current?
Answer:
Electron

Question 12.
Why do most liquids conduct electricity?
Answer:
Due to the presence of ions in them, most liquids conduct electricity.

Question 13.
An LED is more efficient device than a bulb. Why?
Answer:
LED is more efficient because it can glow even when a weak or less current flows through it.

Question 14.
Do lemon juice or vinegar conduct electricity?
Answer:
Yes, they conduct electricity.

Question 15.
How is conductivity of liquids tested?
Answer:
By using a tester.

Question 16.
Is water from taps, handpumps, wells and ponds a good conductor?
Answer:
Yes, water from these sources is a good conductor.

Question 17.
What makes distilled water a good conductor?
Answer:
Salts when mixed with distilled water make it a good conductor.

Question 18.
Why is a layer of zinc coated over iron?
Answer:
To prevent iron from corrosion and rust.

Question 19.
Will the solution of sugar in distilled water conduct electricity?
Answer:
No

Question 20.
Why is tin electroplated on iron to make cans used for storing food?
Answer:
Tin is less reactive than iron. Tin coating prevents food from coming in contact with iron and thus pre¬vents it from getting spoiled or corroded.

Question 21.
Why we ifse chromium electroplating on taps and bars of bicycle instead of silver and gold?
Answer:
Silver and gold are very expensive comparatively to chromium.

Question 22.
What type of effect of current do the deposits of metal on electrodes show?
Answer:
Chemical effect

Question 23.
What effect of current does electroplating show?
Answer:
Chemical effect

Question 24.
Which effect of current causes the bulb to glow?
Answer:
Heating effect

Question 25.
Which part of the bulb glows?
Answer:
Filament

Question 26.
Name the three effects of electric current.
Answer:
Heating, magnetic and chemical effect.

Question 27.
How can the magnetic effect of current be checked?
Answer:
By using magnetic compass.

Question 28.
What do we see when the compass needle is brought near a wire in which current is flowing?
Answer:
The needle deflects.

Question 29.
What is electroplating?
Answer:
Deposition of thin layer of a metal over other metal by electrolysis is called electroplating.