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In case of four wires of same… (Class 10 Science 2024, Q14)

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ScienceCBSE Class 10 · Board exam 2024, set 31/3/1 · 1 mark · MCQ

CBSE Class 10 Science 2024: question 14

Set in the CBSE Class 10 board exam of 2024, paper 31/3/1, section A, question 14, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q14 · 1 mark · MCQElectricity

In case of four wires of same material, the resistance will be minimum if the diameter and length of the wire respectively are

  1. (A)D/2 and L/4
  2. (B)D/4 and 4L
  3. (C)2D and L
  4. (D)4D and 2L

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/3/1.

Hints

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

Hint 1

Resistance depends on length and on cross-sectional area.

Hint 2

Area is proportional to . Compute for each option.

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. , so .

  2. Compare for each option: (A) ; (B) ; (C) ; (D) .

  3. (D) has the smallest value, so its resistance is minimum. Option (D).

    1 mark

Answer: 4D and 2L, option (D)

Where the marks are

  • Uses and finds the minimum for 4D, 2L (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 paper2024 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.