Practice portal › Current Electricity › Resistance and Resistivity

The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is 31.4 cm. The diameter of wire is measured as 2.4 cm. The resistivity of the given wire is measured as x×10⁻³ Ω cm. The value of x is ______. [Take π=3.14] [Figure: graph of potential (volt) on the vertical axis against I (A) on the horizontal axis; a straight line through the origin making 45° with the current axis.]

Asked in JEE Main 29th June 1st Shift 2022 · Resistance of a wire and stretching

Figure: Resistance of a wire and stretching
Answer: 144

Step-by-step solution

Slope of V against I is R=tan 45°=1 Ω.

Area A=π(d/2)²=3.14×(1.2)²=4.5216 cm².

ρ=(RA)/l=(1×4.5216)/(31.4)=0.144 Ω cm.

ρ=144×10⁻³ Ω cm, so x=144.

More Resistance and Resistivity questionsAll Resistance and Resistivity questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer