electron emittes with negligible speed from an electron gun and acceleratd through potential difference V along X-axis. these electrons emerge from a narrow hole into a uniform magnetic field B directed along this axis however some of electrons emerging from hole make slightly divergent angles as shown in figure. show that these divergent parraxial electron are refocussed on the X-axis at distance

[8²mV/eB²]^1/2

Aditi Chauhan , 11 Years ago

Grade 10