Figure shows a rod AB that can rotate with uniform angular velocity $ω$ over a stationary conducting circular frame and resistance R is connected between centre A and frame.

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

If the current was found to be I then the charge to mass ratio of electrons would be $\frac{ω^{2} l^{2}}{2 I R}$

If the current was found to be I then the charge to mass ratio of electrons would be $\frac{2 ω^{2} l^{2}}{I R}$

If a magnetic field B is applied perpendicular to plane of the paper then induced current in rod will be radially outward

If a magnetic field B is applied perpendicular to plane of the paper then induced current (due to
motional emf only) in rod will be $\frac{1}{2} \frac{B l^{2} ω}{R}$

answer is A, C.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

Due to centrifugal force electrons are moving from A to B. At equilibrium, Electric force due to induce charges become equal to centrifugal force $m ω^{2} x = e E$
$\int_{0}^{l} m ω^{2} x d x = \int_{0}^{l} e E d x = e \int_{0}^{l} E d x \Rightarrow \frac{m ω^{2} l^{2}}{2} = e v (v = v o l t a g e a c r o s s r o d) \Rightarrow v = i R = \frac{m ω^{2} l^{2}}{2 e} \Rightarrow \frac{e}{m} = \frac{ω^{2} l^{2}}{2 i R}$

Question Image