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The electric circuit… (Class 10 Science SQP 2024-25, Q25A)

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ScienceCBSE Class 10 · Sample paper, session 2024-25 · 2 marks · Very short answer

CBSE Class 10 Science sample paper 2024-25: question 25(A)

From the official CBSE sample question paper for 2024-25, section B, question 25(A), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q25(A) · 2 marks · Very short answerElectricity

The electric circuit (above figure) in a clothes dryer contains two heaters X and Y in parallel. The figure shows the circuit connected to a 230 V power supply. When both switches are closed, the current in X is 3.5 A.
Analyse the circuit given above and answer the following questions.
(i) Calculate the power developed in heater X.
(ii) If the resistance of X is double that of Y calculate the current in heater Y.

Figure in the paper: 230 V supply connected to two parallel branches, each with a switch in series with a heater: X (upper) and Y (lower). See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

Power in terms of voltage and current is .

Hint 2

In a parallel circuit, which quantity is the same for both heaters?

Hint 3

If V is fixed and R is halved, what happens to ?

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) Power in heater X:

    1 mark

  2. (ii) X and Y are in parallel, so both have the same p.d. of 230 V. By Ohm's law , so at constant the current is .

    ½ mark

  3. , so

    ½ mark

Answer: (i) 805 W; (ii) 7.0 A

Where the marks are

  • Uses to get 805 W (1 mark)
  • Reasons that in parallel (same V) (0.5 mark)
  • Current in Y = 7.0 A (0.5 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 paperSample paper 2024-25: 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.