Skip to content

Explain in brief the function… (Class 10 Science 2024, Q32)

questionbuddy.in/q/cbse-10-science-2024-31-3-1-q32-brief-function-electric-fuse-domestic

ScienceCBSE Class 10 · Board exam 2024, set 31/3/1 · 3 marks · Short answer

CBSE Class 10 Science 2024: question 32

Set in the CBSE Class 10 board exam of 2024, paper 31/3/1, section C, question 32, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q32 · 3 marks · Short answerElectricity

Explain in brief the function of an electric fuse in a domestic circuit. An electric heater of current rating 3 kW; 220 V is to be operated in an electric circuit of rating 5 A. What is likely to happen when the heater is switched 'ON' ? Justify your answer with necessary calculation.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/3/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Which effect of current makes a fuse wire melt?

Hint 2

Find the current drawn by the heater using power and voltage.

Hint 3

Compare that current with 5 A.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Function of fuse: A fuse is a short wire of low melting point connected in series with the circuit. If excess current flows because of overloading or a short circuit, the wire heats up (Joule heating), melts and breaks the circuit. This protects the appliances and the wiring from damage.

    1 mark

  2. Given: , . Formula used: .

    ½ mark

  3. 1 mark

  4. Conclusion: The heater draws about 13.6 A, which is more than the 5 A rating of the circuit. When the heater is switched ON, the fuse wire will melt and break the circuit, and the heater will not work in this circuit.

    ½ mark

Answer: The fuse protects against overloading and short circuits by melting. The heater draws I = 3000/220 ≈ 13.6 A > 5 A, so the fuse will blow and the circuit will break.

Where the marks are

  • Function of fuse: melts on excess current, protecting circuit and appliances (1 mark)
  • Uses P = VI (½ mark)
  • Calculates I ≈ 13.6 A (1 mark)
  • Concludes that the current exceeds 5 A, so the fuse melts (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Electricity, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 31/3/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.