$A$ wire $ab$ of length $l$,mass $m$,and resistance $R$ slides on a smooth,thick pair of metallic rails joined at the bottom as shown in the figure. The plane of the rails makes an angle $\theta$ with the horizontal. $A$ vertical magnetic field $B$ exists in the region. If the wire slides on the rails at a constant speed $v$,then which of the following can be correct for $B$?

  • A
    $B = \sqrt {\frac{{mgR}}{{v{l^2}\,\cos\, \theta }}} $
  • B
    $B = \sqrt {\frac{{mgR\,\sin \,\theta }}{{v{l^2}\,\cos \,\theta }}} $
  • C
    $B = \sqrt {\frac{{mgR\,\sin \,\theta }}{{v{l^2}\,{{\cos }^2}\,\theta }}} $
  • D
    $B = \sqrt {\frac{{mgR\,\sin \,\theta }}{{v{l^2}}}}$

Explore More

Similar Questions

$A$ copper disc of radius $0.1 \ m$ is rotated about its centre with $10$ revolutions per second in a uniform magnetic field of $0.1 \ T$ with its plane perpendicular to the field. The e.m.f. induced across the radius of the disc is:

Figure $(i)$ shows a conducting loop being pulled out of a magnetic field with a speed $v$. Which of the four plots shown in figure $(ii)$ may represent the power delivered by the pulling agent as a function of the speed $v$?

$A$ $20\,cm$ long metallic rod is rotated with $210\,rpm$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. $A$ constant and uniform magnetic field of $0.2\,T$ parallel to the axis exists everywhere. The emf developed between the centre and the ring is $.......\,mV$. Take $\pi=\frac{22}{7}$.

$A$ conductor $ABCD$ is moving with speed $V$ along the $X$-axis in a region where the magnetic field is uniform and directed into the plane of the paper. Between which points is the maximum induced emf produced?

Two metallic rings of radius $R$ are rolling on a metallic rod. $A$ magnetic field of magnitude $B$ is applied in the region. The magnitude of the potential difference between point $A$ and point $C$ on the two rings (as shown) will be:

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo