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Anannya responded to… (Class 10 Science SQP 2023-24, Q33)

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ScienceCBSE Class 10 · Sample paper, session 2023-24 · 3 marks · Short answer

CBSE Class 10 Science sample paper 2023-24: question 33

From the official CBSE sample question paper for 2023-24, section C, question 33, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q33 · 3 marks · Short answerCompetency-basedElectricity

Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three pin plug, whereas an electric bulb can be connected with a two pin plug?

She wrote: Three pin connections reduce heating of connecting wires.

  1. (i)

    Is her answer correct or incorrect? Justify.

    2 marks
  2. (ii)

    What is the function of a fuse in a domestic circuit?

    1 mark

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

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

Hint 1

What is the third pin of a three-pin plug connected to?

Hint 2

Think about what happens if a live wire touches the metal body of an appliance.

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. (i) Anannya's answer is incorrect. A three-pin connection does not reduce heating of the connecting wires.

    1 mark

  2. The third pin connects the metallic body of the appliance to the earth wire. If current leaks to the metal body, the earth wire gives it a low-resistance path to the ground. This keeps the body at earth potential, so the user does not get a severe electric shock. An electric bulb has no metallic body that a user touches, so a two-pin plug is enough.

    1 mark

  3. (ii) A fuse is a safety device connected in series in the circuit. It protects the circuit and appliances from overloading and short-circuiting. When excess current flows, its wire (of low melting point) melts and breaks the circuit.

    1 mark

Answer: (i) Incorrect: the third pin provides earthing, a low-resistance path for leakage current that protects the user from shock. (ii) A fuse melts and breaks the circuit when excess current flows, protecting the circuit and appliances.

Where the marks are

  • States that the answer is incorrect (1 mark)
  • Explains that the earth wire gives a low-resistance path for leakage current from the metal body (1 mark)
  • Function of fuse: melts on excess current and breaks the circuit (1 mark)

Revise the chapter

  • Chapter: Electricity (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Electricity, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2023-24: 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.