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Use Ohm's law to determine… (Class 10 Science 2024, Q25)

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 2 marks · Very short answer

CBSE Class 10 Science 2024: question 25

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section B, question 25, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q25 · 2 marks · Very short answerElectricity

Use Ohm's law to determine the potential difference across the resistor in the circuit shown in the following diagram when key is closed :

Figure in the paper: Circuit diagram: a rectangular loop containing a key K, a 2 V cell (positive terminal marked +), a resistor on the upper right side, a resistor on the lower left side and a resistor on the lower right side, all in series in the loop. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

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

Hint 1

All resistors are in one loop, so they are in series.

Hint 2

Find the total resistance, then the current, then use for the resistor only.

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. All three resistors are in series with the 2 V cell, so the total resistance is .

    ½ mark

  2. By Ohm's law, the current in the circuit is .

    ½ mark

  3. A. The same current flows through every resistor because they are in series.

    ½ mark

  4. Potential difference across the resistor: V.

    ½ mark

Answer: 1 V

Where the marks are

  • Equivalent series resistance (½ mark)
  • Writes Ohm's law (½ mark)
  • Current A (½ mark)
  • V across the resistor (½ 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 paper2024 board paper, set 31/2/1: 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.