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Answer the following. (Science 2026 31/3/1 Q36)

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ScienceCBSE Class 10 · Board exam 2026, set 31/3/1 · 3 marks · Short answer

CBSE Class 10 Science 2026: question 36

Set in the CBSE Class 10 board exam of 2026, paper 31/3/1, section C, question 36, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q36 · 3 marks · Short answerElectricity

Answer the following.

  1. (a)

    Name a device which is used to :
    (i) Maintain a constant potential difference in a circuit.
    (ii) Change the electric current in an electric circuit.

    0 marks
  2. (b)

    When the potential difference between the terminals of an electric heater is 110 V, a current of 5 A flows through it. What will be the value of current flowing through it when the potential difference is increased to 220 V ?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/3/1.

Hints

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

Hint 1

Which device supplies a steady potential difference, and which one lets you vary resistance?

Hint 2

The heater's resistance does not change. Find it first from the given data.

Hint 3

Use Ohm's law again with the new voltage.

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. (a)(i) A battery / electric cell maintains a constant potential difference in a circuit.

    ½ mark

  2. (a)(ii) A rheostat (variable resistance) is used to change the current in a circuit.

    ½ mark

  3. (b) By Ohm's law, the resistance of the heater is .

    ½ mark

  4. ½ mark

  5. The resistance stays the same, so the new current is .

    ½ mark


  6. (Equivalently: , so doubling the potential difference doubles the current, from 5 A to 10 A.)

    ½ mark

Answer: (a)(i) Battery/cell; (ii) Rheostat. (b) R = 22 Ω, current = 10 A

Where the marks are

  • Battery/electric cell (½ mark)
  • Rheostat/variable resistance (½ mark)
  • Uses R = V/I (½ mark)
  • R = 22 Ω (½ mark)
  • Uses I′ = V′/R (½ mark)
  • I′ = 10 A (½ mark); the alternative V ∝ I argument also earns full credit

Revise the chapter

  • Chapter: Electricity (notes, formulas, where marks are lost and every past question)
  • Topic: Ohm's Law
Practise this chapterBoard-style questions from Electricity, one at a time, marked against the answer key and marking points.Back to the full paper2026 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.