An electrostatically defecting CRT has plane parallel plates 2.5 cm long & 0.5 cm apart, with the distance from their centre to screen being 20 cm. If the electron beam is accelerated by a potential difference of 2500V under the defecting voltage of 200V, calculate beam speed, the deflection factor of the tube & beam deflection on the screen.

Subject: Applied Physics 2

Topic: Motion Of Charged Paqrticle In Electric And Magnetic Field

Difficulty: Medium

$$ $$ $ l = 2.5 cm, \\ d= 0.5 cm, \\ D =20 cm. \\ V_A = 2500 V, \\ V = 200 V \\ Y = (D l V) / (2 dVA ) \\ Y=(20 * 2.5*200) / (2*0.5*500 ) \\ Y = 4 cm \\ \text{Beam speed }v= √(2VA e/m) \\ v= √(2*2500* (10^{-19}*1.6) / (9.1 * 10^{-31} )) \\ v= 2.9*10^7 m/s \\ $