CBSE Class 8 Science Chapter 11 Chemical Effects Of Electric Current MCQs

CBSE Class 8 Science Chapter 11 Chemical Effects Of Electric Current Multiple Choice Questions

Question 1. Plastic wire is

1. An insulator
2. A conductor
3. Both 1 and 2
4. None of these

Answer: 1. An insulator

Question 2. Electrolytes conduct electricity due to the movement of

1. Electrodes
2. Atoms
3. Electrons
4. Ions

Answer: 4. Ions

” Cbse Class 8 Science Chapter 11 Mcqs “

Read And Learn More CBSE Class 8 Science Multiple Choice Questions

Question 3. The solution that can conduct electricity is of

1. Pure water
2. Water and acid solution
3. Water and salt solution
4. Both B and C

Answer: 3. Water and salt solution

” Chemical Effects Of Electric Current Mcqs “

Question 4. Which one of the following solutions will not conduct electricity?

1. Lemon rice
2. Vinegar
3. Tap water
4. Vegetable oil

Answer: 4. Vegetable oil

Question 5. Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B as shown in figure.

” Conductivity Of Liquids Class 8 “

They found that the bulb in setup A glows more brightly as compared to that of setup B. You would conclude that

1. Higher Current Is Flowing Through The Circuit In Set Up A
2. Higher Current Is Flowing Through The Circuit In Set B
3. Equal Current Is Flowing Through Both The Circuits
4. The Current Flowing Through The Circuits In The Two Setups Cannot Be Compared In This Manner

Answer: 1. Higher Current Is Flowing Through The Circuit In The Setup A

Question 6. Observe the following circuits. In which circuit will the bulb glow? Write ‘Yes’ or ‘ No’ in the blank space provided along with each of the circuits given in the figure.

” Electroplating Process Class 8 “

Answer:

1. No
2. Yes
3. No
4. Yes

Question 7. Observe the figure.

Which of these two circuits, A or B, shows the correct observation? It is not clear from the diagram what A and B.

So cannot predict the actual solution. But if we compare with the activity. This seems to be a potato, and the correct diagram is A because the positive terminal makes the green spot on the potato.

Question 8. 

” Lemon Juice And Vinegar Conductivity “

Which of the following solutions will not make the bulb glow in the figure?

1. Sodium chloride
2. Copper sulphate
3. Silver nitrate
4. Sugar solution in diluted water

Answer: 4. Sugar solution in diluted water

Question 9. The process of depositing a thin layer of any superior metal over an object made of a cheaper metal with the help of electricity is called

1. Electro refining
2. Electro-metallurgy
3. Electroplating
4. None Of the Above

Answer: 3. Electroplating

Question 10. Which of the following metals is used in electroplating to make objects appear shiny?

1. Iron
2. Copper
3. Chromium
4. Aluminium

Answer: 3. Chromium

Question 11. Boojho’s uncle has set up an electroplating factory near his village. He should dispose of the waste of factory waste

1. In the nearby river
2. In the nearby pond
3. In the nearby corn field
4. According to the disposal guidelines of the local authority

Answer: 4. According to the disposal guidelines of the local authority.

” Magnetic Needle Deflection Experiment “

CBSE Class 8 Science Short Answer Type Questions

Question 12. Boojho made the circuit as shown in the figure. He wanted to observe what happens when an electric current is passed through water, but he forgot to add a few drops of lemon juice to the water. Will it make any difference to his observations? Explain

Answer: Adding few drops of lemon juice in water will increase the conductivity of the solution. The current will flow in both the cases but adding of lemon juice makes it easy for the current to flow.

” Bulb Glowing In Circuits “

Question 13. Observe the following circuit given in the figure.

Current does not flow in the circuit if there is a gap between the two wires. Does It Indicate that air is a poor conductor of electricity? Does air never conduct electricity? Explain.?
Answer: Yes, current is not flowing through the air gap between the wires, It means that air Is a poor conductor of electricity.

Air conducts electricity only when there is a great voltage or when there is some moisture in the air.

” Distilled Water And Salt Solution “

Question 14. Boojho made the circuit given in Figure and observed that the bulb did not glow. On Paholl’s suggestion, he added one more cell in the circuit. The bulb now glows. Explain.

Answer: Initially, the bulb was not glowing because the voltage required to make the bulb glow was not sufficient. When the voltage increases more than a particular value, the bulb starts glowing because it gets sufficient energy to heat its filament.

” Cbse Class 8 Science Mcqs “

Question 15. Paheli setup an experiment using liquid A in the beaker as shown in figure. She observed that the bulb glows. Then, she replaced the liquid A by another liquid B. This time the bulb did not glow. Boojho suggested replacing the bulb by an LED. They observed that the LED glows. Explain.

A is a good conductor of electricity, and it allows the maximum current to pass through it, which is sufficient to glow the bulb.

But when it is replaced by another liquid B, the bulb does not glow because liquid B is not a good conductor of electricity. But the small current which is passing through B is sufficient to glow a low-voltage LED, so it glows.