Three sets of voltage–current readings were taken for a wire at room temperature:

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

Three sets of voltage–current readings were taken for a wire at room temperature: (i)

V=2.00\,\text V

I=0.40\,\text A

(ii)

V=3.08\,\text V

I=0.62\,\text A

(iii)

V=4.90\,\text V

I=0.98\,\text A

If the wire is considered ohmic when the percentage variation of resistance across readings does not exceed 1 %, the correct assessment is (a)

\text{Percentage variation}\approx 0.7\%,\ \text{wire is ohmic}

(b)

\text{Percentage variation}\approx 2.5\%,\ \text{wire is non-ohmic}

(c)

\text{Percentage variation}\approx 0.4\%,\ \text{wire is ohmic}

(d)

\text{Percentage variation}\approx 0.7\%,\ \text{wire is non-ohmic}