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In a certain region of space electric fi...

In a certain region of space electric field E and magnetic field B are perpendicular ot each other and an electron enters region perpendicular to the direction of B and E both and moves undeflected, then velocity of electron is

A

`(|overset(to)E|)/(|overset(to)B|)`

B

`overset(to) ( E ) xx overset(to)( B) `

C

`(|overset(to)B|)/(|overset(to)E|)`

D

`overset(to)( E ) .overset(to)( B )`

Text Solution

Verified by Experts

The correct Answer is:
A
For electron to pass undeflected,
Electric force on electron = magnetic force on electron
i.e., `eE = ev B`
or `v = ( E )/( B)`
or `v = (|overset(to)E|)/(|overset(to)B|)`
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Knowledge Check

  • Assertion: EM wave are transwers in nature. Reason: The electric and magnetic fields of an e.m. wave are perpendicular to each other also perpendicular to the direction of wave propagation.

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