When the potential difference V across a conductor is plotted against the current I through it, a straight li…

Question

When the potential difference V across a conductor is plotted against the current I through it, a straight line passing through the origin is obtained. What does the slope of this V–I graph represent?

Accepted Answer

## Model Answer The slope of the V–I graph represents the **resistance (R)** of the conductor. According to Ohm's law, $V \propto I$ (at constant temperature), which gives: $$\frac{V}{I} = R = 	ext{constant}$$ Since the graph is a straight line through the origin, its slope = $\frac{V}{I}$ = R. Thus, the slope gives the resistance of the conductor, measured in **ohms (Ω)**. A steeper slope means higher resistance, meaning the conductor opposes the flow of current more strongly. *Source: Chapter 11, Section 11.4 — Ohm's Law* --- ## Explanation - The examiner expects you to clearly name **resistance** as what the slope represents. - State Ohm's law ($V = IR$) and rearrange to show slope = $V/I = R$. - Mention the SI unit **ohm (Ω)** — this is often a separate mark. - Optionally link slope steepness to higher resistance for a complete answer in a 3-mark question. - Never say "the slope is Ohm's law" — say the slope **represents resistance**.

Science (086) — AI-generated practice question