The values of current I flowing in a given resistor for the corresponding values of potential difference V applied across the ends of resistor are given below in the table :
Plot a graph between V and I and calculate the resistance of that resistor.
Generated by claude-sonnet-4-6 · 2026-06-15 06:42 · grounding rag
Model Answer
Graph: Plot V on the x-axis and I on the y-axis. The points (1.2, 0.4), (2.4, 0.8), (3.6, 1.2), (4.8, 1.6), (6.0, 2.0) lie on a straight line passing through the origin, showing that V ∝ I (Ohm's law is verified).
Calculation of Resistance:
Using Ohm's law: $R = \dfrac{V}{I}$
Taking any point, say V = 6.0 V, I = 2.0 A:
$$R = \frac{V}{I} = \frac{6.0 \text{ V}}{2.0 \text{ A}} = 3 \text{ Ω}$$
The resistance of the resistor is 3 Ω.
Source: Chapter 11, Section 11.4 — Ohm's Law
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Explanation
- Graph (1 mark): Plot the given points with V on x-axis and I on y-axis; the straight line through the origin confirms Ohm's law. CBSE expects you to mention the nature of the graph.
- Resistance (2 marks): Use $R = V/I$ with any consistent pair of values — all pairs give the same ratio (3 Ω) since V/I is constant. Show the formula, substitution, and unit.
- The slope of the V–I graph = V/I = R, so the graph itself gives resistance. Mentioning this earns full credit.