Question

An electron gun fires electrons at the screen of a television tube. The electrons start from rest and are accelerated through a potential difference of 60,000 V. What is the speed of the electrons JUST BEFOREthey strike the screen? Ignore relativistic effects. (Answer in m/s)

Answer 1

1.45255 x 10⁸ m/s

Step-by-step explanation:

q = magnitude of charge on the electron = 1.6 x 10⁻¹⁹ C

m = mass of the electron = 9.1 x 10⁻³¹ kg

v = speed of the electron

ΔV = potential difference = 60,000 Volts

Using conservation of energy

Kinetic energy gained by the electron = Electric potential energy

(0.5) m v² = q ΔV

(0.5) (9.1 x 10⁻³¹ ) v² = (1.6 x 10⁻¹⁹) (60,000)

v = 1.45255 x 10⁸ m/s