📚 CBSE Grade-10 Study Guide Open in the Study Guide single page app →
HomeScience

Science — CBSE Class 10 board question

Q1. [4]
In our homes, we receive the supply of electric power through a main supply also called mains, either supported through overhead electric poles or by underground cables. In our country the potential difference between the two wires (live wire and neutral wire) of this supply is 220 V.
Read the passage carefully and answer the questions that follow.
  1. (a) Write the colours of the insulation covers of the line wires through which supply comes to our homes. [1]
  2. (b) What should be the current rating of the electric circuit (220 V) so that an electric iron of 1 kW power rating can be operated ? [1]
  3. (c) Answer the following : [2]
Previously asked in CBSE board exam
2025 31/1/1 Q39
Generated by claude-sonnet-4-6 · 2026-06-15 06:43 · grounding stimulus

I notice that sub-question (c) appears to be incomplete — its actual question text is missing. I will answer (a) and (b) fully, and note the issue for (c).

---

Model Answer

(a) The live wire has a red insulation cover and the neutral wire has a black insulation cover. (The earth wire has a green insulation cover.)

(b)
$$I = \frac{P}{V} = \frac{1000 \text{ W}}{220 \text{ V}} \approx 4.5 \text{ A}$$

The current rating of the circuit should be at least 5 A.

(c) (The question text for sub-question (c) is missing/incomplete in the paper provided. Please supply the full question for a complete answer.)

Source: Chapter 12 – Electricity, Section: Domestic Electric Circuits

---

Explanation
If a question refers to an image, map, graph or diagram that is not shown here, open the Study Guide single page app, go to Library and find the actual CBSE question paper. The original papers are also available on the CBSE website: cbse.gov.in.
Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.