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The resistance of a resistor… (Class 10 Science 2023, Q15)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 15

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section A, question 15, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q15 · 1 mark · MCQElectricity

The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become :

  1. (A)four times
  2. (B)two times
  3. (C)half
  4. (D)one fourth

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

Which quantity stays fixed when only the resistor is changed?

Hint 2

Use the form of Joule's law that contains V.

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. With the potential difference V and time t unchanged, the heat produced is .

  2. If , then . The heat becomes two times, so option (B) is correct.

    1 mark

Answer: Two times, option (B)

Where the marks are

  • Uses H = V²t/R to get double the heat (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 paper2023 board paper, set 31/4/1: 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.