From the null point condition of a Meter Bridge, it follows that,
604.5Ω=100−60X⇒X=6040×4.5Ω=3Ω
Also,
X==Aρlπr2ρl...(1)
From equation (1), it follows that
3=ρ×π×(7×10−4)20.1⇒ρ=0.13×π×(7×10−4)2≈66×10−7Ωm
Therefore, R=66.
JEE Main 2024 — Physics Electromagnetism
A wire of length 10cm and radius 7×10−4m connected across the right gap of a meter bridge. When a resistance of 4.5Ω is connected on the left gap by using a resistance box, the balance length is found to be at 60cm from the left end. If the resistivity of the wire is R×10−7Ωm, then value of R is :
Held on 27 Jan 2024 · Verified 6 Jul 2026.
63
70
66
35
Sign in to track your attempts and accuracy.
Sign in to keep a private note on this question. Nothing you write is ever public.
A square loop of side $2$ cm is placed in a time varying magnetic field with magnitude as $B = 0.4\sin(300t)$ Tesla. The normal to the plane of loop makes an angle of $60°$ with the field. The maximum induced emf produced in the loop is __________ mV.
A circular coil of radius $2$ cm and $125$ turns carries a current of $1$ A. The coil is placed in a uniform magnetic field of magnitude $0.4$ T. The axis of the coil makes an angle of $30°$ with the direction of the magnetic field. The torque acting on the coil is $\alpha \times 10^{-4}$ N.m. The value of $\alpha$ is ______. ($\pi=3.14$)
$1\,\mu$C charge moving with velocity $\vec{v} = \left(\hat{i} - 2\hat{j} + 3\hat{k}\right)$ m/s in the region of magnetic field $\vec{B} = \left(2\hat{i} + 3\hat{j} - 5\hat{k}\right)$ T. The magnitude of force acting on it is $\sqrt{\alpha} \times 10^{-6}$ N. The value of $\alpha$ is _______.
A charged particle moves in a uniform magnetic field. If the velocity is perpendicular to the field, the path of the particle is:
Three identical coils $C_{1}, C_{2}$ and $C_{3}$ are closely placed such that they share a common axis. $C_{2}$ is exactly midway. $C_{1}$ carries current $I$ in anti-clockwise direction while $C_{3}$ carries current $I$ in clockwise direction. An induced current flows through $C_{2}$ will be in clockwise direction when
Work through every JEE Main Electromagnetism PYQ, year by year.