why do the electron beam change their speed in an electric field but not in a magnetic field?

Asked by  | 7th Feb, 2012, 09:32: AM

Expert Answer:

when force is applied on a particle, its speed changes.
in electric fld, force on electron=eE and does not depend on direction of motion of electron.
in magnetic fld force on electron=e(v xB) thisv xB is cross product.
so the electon will not change its speed if force applied on it is 0. and this force will be 0 when,velocity of el is in the direction of the magnetic fld.
so motion of el is along magnetic fld, so force on the el is 0 and it s speed remains same.

Answered by  | 7th Feb, 2012, 09:58: AM

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