A beam of electron is accelerated by a potential difference of 2.5okV. The electrons are then allowed to pass into a magnetic field of strength 10.0mT. As the electrons enter the field, the direction of the velocity is at right angles to the direction of the magnetic field. All this takes place in an evacuated chamber. What is the speed of the electron just before it enters the magnetic field?

Ans: i tried Ek= e(deltaV) and also the magnitude of force, however that is not given.

2 answers

E=eV is energy, you have to convert that to KEnergy and velocity.
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