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Question and Answer

What should be the magnitude and direction of electric field?
(A) \(7 Nc^{-1}\), Vertically up \(\perp\) to velocity
(B) \(7 Nc^{-1}\), horizontally and \(\perp\) to velocity
(C) \(14 Nc^{-1}\), horizontally parallel to velocity
(D) none of these

Answer

Answer: B
\(\vec v\times \vec B=E\)
If angle between B and v is \(\dfrac{\pi}{2}\)
\(v\) = \(\displaystyle \dfrac{E}{B}\)
or \(vB\) = \(14(0.5)\) = \(7 NC^{-1}\)
Thus magnitude of electric field is 7 and direction is horizontal, perpendicular to velocity
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