Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q42 (NDA-II/2018) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

The connecting cable of electrical appliances like electric iron, water heater or contains three insulated copper wires of three different colours- red, green and black. Which one of the following is the correct colour code?

Result
Your answer: —  Â·  Correct: C
Explanation

In domestic electrical wiring in India, the standard colour coding for a three-wire connecting cable ensures safety and proper circuit completion. The live wire (or phase), which carries the current from the power source to the appliance, is typically insulated in red [1]. The neutral wire, which completes the circuit by returning the current to the power supply, is insulated in black [1]. The third wire is the ground (or earth) wire, which is insulated in green; its primary function is to connect the metallic body of the appliance to the earth to prevent electric shocks in case of insulation failure. While international standards have evolved (e.g., brown for live and blue for neutral), the traditional Indian system described in the question consistently uses red for live, black for neutral, and green for ground [2].

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > 12.4 DOMESTIC ELECTRIC CIRCUITS > p. 204
  2. [2] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > What you have learnt > p. 206
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
75%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CDS-II · 2011 · Q94 Relevance score: 0.27

When you pull out the plug connected to an electrical appliance, you often observe a spark. To which property of the appliance is this related ?

CDS-I · 2005 · Q74 Relevance score: -0.10

Consider the following statements: Copper rods are generally preferred to iron rods for making lightning conductors because 1. Copper is a better conductor of electricity than iron. 2. Copper is not easily oxidised under atmospheric conditions. 3. Copper is cheaper and easily available as compared to iron. 4. Specific heat of copper is more than that of iron. Which of the statements given above are correct ?

CDS-I · 2021 · Q51 Relevance score: -0.30

We are given three copper wires of different lengths and different areas of cross-section. Which one of the following would have highest resistivity ?

IAS · 1996 · Q121 Relevance score: -0.53

Domestic electrical wiring is basically a