WBJEE · Physics · Current Electricity
A wire of resistance \(\mathrm{R}\) is elongated \(n\)-fold to make a new uniform wire. The resistance of new wire
- A \(n \mathrm{R}\)
- B \(n^2 \mathrm{R}\)
- C \(2 n \mathrm{R}\)
- D \(2 n^2 \mathrm{R}\)
Answer & Solution
Correct Answer
(B) \(n^2 \mathrm{R}\)
Step-by-step Solution
Detailed explanation
Hints : \(\mathrm{R}^{\prime}=n^2 \mathrm{R}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- The stress along the length of a rod (with rectangular cross-section) is \(1 \%\) of the Young's modulus of its material. What is the approximate percentage of change of its volume? (Poisson's ratio of the material of the rod is \(0.3 .\) )WBJEE 2018 Medium
- A train approaching a railway platform with a speed of \(20 \mathrm{ms}^{-1}\) starts blowing the whistle. Speed of sound in air is \(340 \mathrm{ms}^{-1}\). If the frequency of the emitted sound from the whistle is \(640 \mathrm{Hz}\), the frequency of sound to a person standing on the platform will appear to beWBJEE 2012 Medium
- The dimension of angular momentum isWBJEE 2012 Easy
- A straight conductor \(0.1 \mathrm{m}\) long moves in uniform magnetic field \(0.1 \mathrm{T}\). The velocity the conductor is \(15 \mathrm{m} / \mathrm{s}\) and is directer perpendicular to the field. The emf inducod between the two ends of the conductor isWBJEE 2015 Easy
- A shown in the figure, a liquid is at same levels in two arms of a U-tube of uniform cross-section when at rest. If the \(U\)-tube moves with an acceleration ' \(f\) ' towards right, the difference between liwuid height between two arms of the \(\mathrm{U}\)-tube will be, (acceleration due to gravity \(=\mathrm{g}\) )
WBJEE 2023 Hard - Three identical square plates rotate about the axes shown in the figure in such a way that their kinetic energies are equal. Each of the rotation axes passes through the centre of the square. Then the ratio of angular speeds \(\omega_{1}: \omega_{2}: \omega_{3}\) is
WBJEE 2014 Medium
More PYQs from WBJEE
- The compound that would produce a nauseating smell/odour with a hot mixture of chloroform and ethanolic potassium hydroxide isWBJEE 2017 Easy
- The greatest and least values of \(f(x)=\tan ^{-1} x-\frac{1}{2} \ln x\) on \(\left[\frac{1}{\sqrt{3}}, \sqrt{3}\right]\) areWBJEE 2021 Medium
- A gas bubble of \(2 \mathrm{cm}\) diameter rises througha liquid of density \(1.75 \mathrm{g} \mathrm{cm}^{-3}\) with a fixed speed of \(0.35 \mathrm{cms}^{-1}\). Neglect the density of the gas. The coefficient of viscosity of the liquid isWBJEE 2016 Hard
- One \(\mathrm{Kg}\) of copper is drawn into a wire of \(1 \mathrm{~mm}\) diameter and a wire of \(2 \mathrm{~mm}\) diameter. The resistance of the two wires will be in the ratioWBJEE 2009 Medium
- The locus of the centre of the circles which touch both the circles \(x^{2}+y^{2}=a^{2}\) and \(x^{2}+y^{2}=4\)ax externally isWBJEE 2020 Medium
- A function \(f: \mathbb{R} \rightarrow \mathbb{R}\), satisfies \(f\left(\frac{x+y}{3}\right)=\frac{f(x)+f(y)+f(0)}{3}\) for all, \(x, y \in \mathbb{R}\). If the function ' \(f\) ' is differentiable at \(x=\) 0 , then \(f\) isWBJEE 2025 Hard