JEE Mains · Physics · STD 12 - Moving charges and magnetism
- JEE Mains 2016
- Medium
- MCQ
Consider a thin metallic sheet perpendicular to the plane of the paper moving with speed \('v'\) in a uniform magnetic field \(B\) going into the plane of the paper (See figure). If charge densities \({\sigma _1}\) and \({\sigma _2}\) are induced on the left and right surfaces, respectively, of the sheet then (ignore fringe effects)

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Answer & Solution
Correct Answer
(B) \({\sigma _1} = { \in _0}\,vB\,,\,{\sigma _2} = - { \in _0}\,vB\)
Step-by-step Solution
Detailed explanation
\(\because F=q E\) and \(F=q v B\)
\(\therefore \mathrm{E}=\mathrm{vB}\)
And Gauss's law in Electrostatics \(\mathrm{E}=\frac{\sigma}{\varepsilon_{0}}\)
\(\mathrm{E}=\frac{\sigma}{\varepsilon_{0}}=\mathrm{vB} \Rightarrow \sigma=\varepsilon_{0} \mathrm{vB}\)
\(\sigma_{1}=-\sigma_{2}\)
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