Задача 30368.

The flat capacitor between the plates is an electric field strength of E = 100 V / m, it is placed in a magnetic field so that the field lines are perpendicular fields. What should be in the induction of the magnetic field to the electron with initial energy T = 4 keV, had entered with a space between the capacitor plates perpendicular to the magnetic field lines, not change direction of speed?

Detailed solution shorthand terms, formulas and laws used in the decision, the withdrawal of the calculation formula and the response.
If you have any questions to address, please. I´ll try to help.