Unit Test: Electricity: Circuits and their Components | Science (Curiosity) Class 7 - New NCERT PDF Download

Maximum Marks: 30
Attempt all questions

• Question numbers 1 to 7 carry 1 mark each.
• Question numbers 8 to 12 carry 2 marks each.
• Question numbers 13 to 15 carry 3 marks each.
• Question numbers 16 carry  4 marks each.

Q1. What is the source of electrical energy in a torchlight? (1 Mark)
(i) Switch
(ii) Electric cell
(iii) Filament
(iv) Wire

​Q2. The thin wire inside an incandescent lamp that glows is called the __________. (1 Mark)

Q3. Which of the following is a characteristic of an LED? (1 Mark)
(i) It has a filament
(ii) It allows current to flow in both directions
(iii) It has a positive and negative terminal
(iv) It requires four cells to glow

​Q4. What is the purpose of a switch in an electrical circuit? (1 Mark)

​Q5. Which material is commonly used for making electrical wires? (1 Mark)
(i) Plastic
(ii) Rubber
(iii) Copper
(iv) Glass

​Q6. Materials that do not allow electric current to pass through are called __________. (1 Mark)

​Q7. Why does an LED glow only in one specific connection? (1 Mark)
(i) It has a filament
(ii) Current flows through it in one direction only
(iii) It requires a switch
(iv) It uses multiple cells

​Q8. Explain the difference between a conductor and an insulator. (2 Mark)

​Q9. Why is it important to connect cells in a specific order in a battery? (2 Mark)

​Q10. How does an incandescent lamp produce light? (2 Mark)

​Q11. What is an electrical circuit, and why is it necessary for a lamp to glow? (2 Mark)

​Q12. Why are electrical wires covered with plastic or rubber? (2 Mark)

Q13.  How do electric cells or batteries make the use of electrical devices more convenient, and what are some examples of their different forms and uses? (3 Mark)

​Q14. Explain how a battery is formed and its advantage over a single cell. (3 Mark)

Q15. Write the components of an electrical circuit and draw the symbols with which they can be represented. (3 Mark)

Q16. Read the following passage and answer the questions that follow. (4 Mark)
Nihal and his friends were excited to explore how torchlights work. During a classroom activity, they dismantled a torch and observed components like the electric cells, a switch, and a lamp. They noticed the lamp glowed only when the cells were placed in a certain order and the switch was turned on. Later, they used the same components—two electric cells, a lamp holder, wires, and a switch—to construct a circuit on a cardboard base. Surprisingly, in some arrangements, the lamp did not glow even when the switch was on. After multiple trials, they learned the importance of making a complete circuit and ensuring the proper connection of terminals.
Answer the following:
(a) Why did the lamp not glow in some arrangements even when the switch was on?
(b) What is meant by a complete circuit, and why is it necessary?
(c) What happens if the wire connections are loose or the filament of the lamp is broken?
(d) State the direction of electric current in a circuit using an electric cell.

You can access the solutions to this Unit Test here.