Mathematics in Physics

JEE Main level, single correct, medium

69 of 121

Question 69 of 121

If the percentage errors in measuring the length and the diameter of a wire are 0.10.1% each. The percentage error in measuring its resistance will be:

Show answer and solution

Answer: (B) 0.30.3%

Resistance of the wire in terms of the diameter can be written as, R=ρLπd24R=\dfrac{\rho L}{\pi \dfrac{{d}^{2}}{4}}
Hence, percentage error relation will be, ∆RR×100=∆LL×100+2∆dd×100\dfrac{∆R}{R}\times 100=\dfrac{∆L}{L}\times 100+\dfrac{2∆d}{d}\times 100
Given: ∆LL=0.1\dfrac{∆L}{L}=0.1% and ∆dd=0.1\dfrac{∆d}{d}=0.1%
Therefore, ∆RR=0.3\dfrac{∆R}{R}=0.3%

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.

More Physics practice

JEE Main Physics practice question on Mathematics in Physics (Errors of Measurement), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.