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The position of the needle is… (Class 10 Science 2023, Q15)

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

CBSE Class 10 Science 2023: question 15

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

Q15 · 1 mark · MCQElectricity

In the following diagram, the position of the needle is shown on the scale of a voltmeter. The least count of the voltmeter and the reading shown by it respectively are :

  1. (A)0.15 V and 1.6 V
  2. (B)0.05 V and 1.6 V
  3. (C)0.15 V and 1.8 V
  4. (D)0.05 V and 1.8 V

Figure in the paper: Semicircular voltmeter scale from 0 (left) to 3 (right), with 1.5 marked at the top centre. The needle pivots at the centre (labelled V) and points to the right of the 1.5 mark, between divisions. See it in the official paper.

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

Hints

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

Hint 1

Divide the value between two labelled marks by the number of divisions between them.

Hint 2

Count how many divisions the needle is past 1.5 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. Least count = (value of one main interval) ÷ (number of small divisions in it). The scale has 10 divisions between 0 and 1.5 V, so LC V.

  2. The needle stands 2 divisions beyond the 1.5 V mark. Reading V. So the answer is (C).

    1 mark

Answer: LC = 0.15 V, reading = 1.8 V; option (C)

Where the marks are

  • Finds least count 0.15 V and reading 1.8 V (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 31/1/1: 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.