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Let the resistance of an… (Class 10 Science 2023, Q24)

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ScienceCBSE Class 10 · Board exam 2023, set 31/6/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 24

Set in the CBSE Class 10 board exam of 2023, paper 31/6/1, section B, question 24, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q24 · 2 marks · Very short answerElectricity

Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/6/1.

Hints

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

Hint 1

Which law links V, I and R?

Hint 2

Keep R fixed and replace V by V/4 in that relation.

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. By Ohm's law, . With constant, . So the current becomes one-fourth of its original value.

    1 mark

  2. Ohm's law: the potential difference across the ends of a conductor is directly proportional to the current through it, provided the temperature remains the same: , or .

    1 mark

Answer: Current becomes one-fourth of its initial value; Ohm's law.

Where the marks are

  • Current reduces to one-fourth (1 mark)
  • Correct statement of Ohm's law with the condition of constant temperature (1 mark)

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 paper2023 board paper, set 31/6/1: 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.