Skip to content

Answer the following. (Science 2023 31/5/1 Q36)

questionbuddy.in/q/cbse-10-science-2023-31-5-1-q36

ScienceCBSE Class 10 · Board exam 2023, set 31/5/1 · 5 marks · Long answer

CBSE Class 10 Science 2023: question 36

Set in the CBSE Class 10 board exam of 2023, paper 31/5/1, section D, question 36, for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q36 · 5 marks · Long answerElectricity

Answer the following.

  1. (a)

    State Ohm's Law.

    0 marks
  2. (b)

    Name and define the physical quantity determined by the slope of V – I curve given in the diagram. Use this graph to find the value of this physical quantity in SI units.

    0 marks
  3. (c)

    Establish the relationship between 1 kWh and 1 joule.

    0 marks

Figure in the paper: V–I graph. Y-axis: Potential Difference (V), marked 1.5, 3.0, 4.5, 6.0. X-axis: Current (A), marked 0.2, 0.4, 0.6, 0.8. A straight line passes through the origin and reaches approximately (0.8 A, 6.0 V), showing a linear, proportional relationship. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/5/1.

Hints

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

Hint 1

Ohm's law links V and I. Remember the condition under which it holds.

Hint 2

The slope of a V (y-axis) against I (x-axis) graph is V/I. Which quantity is that?

Hint 3

For (c), write 1 kW in J/s and 1 h in seconds, then multiply.

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. (a) Ohm's law: The potential difference across the ends of a metallic wire is directly proportional to the current through it, provided its temperature stays the same. So , i.e. .

    1 mark

  2. (b) The slope of the V–I graph gives the resistance . Resistance is the property of a conductor by which it opposes the flow of charge (current) through it.

    1 mark

  3. From the graph, take the origin and the point :

    1 mark

  4. ½ mark

  5. SI unit: ohm, so .

    ½ mark

  6. (c)

    1 mark

Answer: (a) V ∝ I at constant temperature (V = IR); (b) resistance, R = 7.5 Ω; (c) 1 kWh = 3.6 × 10⁶ J

Where the marks are

  • Correct statement of Ohm's law, including the constant-temperature condition (1 mark)
  • Names resistance and defines it as opposition to the flow of charge (1 mark)
  • Uses slope = ΔV/ΔI with readings taken from the graph (1 mark)
  • Gets the value 7.5 (½ mark)
  • Gives the unit Ω (½ mark)
  • Shows 1 kWh = 1000 J/s × 3600 s = 3.6 × 10⁶ J (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 31/5/1: 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.