Velocity Selector

2001 AIPMT 1 question

1. 1 Moving Charges and Magnetism Easy
   In Thomson mass spectrograph $\vec{E} \perp \vec{B}$ then the velocity of undeflected electron beam will be :
   A $\dfrac{|\vec{E}|}{|\vec{B}|}$ B $\vec{E} \times \vec{B}$ C $\dfrac{|\vec{B}|}{|\vec{E}|}$ D $\dfrac{E^2}{B^2}$
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