Question

Two insulating plates are both uniformaly charged in such a way that the potential difference between them is V₂ – V₁ = 20V. (i.e. plate 2 is at a higher potential). The plates are separated by d = 0.1 m and can be treated as infinitely large. An electron is released from rest on the inner surface of plate 1. What is its speed when it hits plate 2?

(e = 1.6 × 10^–19C, m_e = 9.11 × 10^–31kg)

(a) 32 × 10^–19m/s 

(b) 2.65 × 10⁶m/s

(c) 7.02 × 10¹²m/s 

(d) 1.87 × 10⁶m/s.

Answer 1

(b) : An electron on plate 1 has electrostatic potential energy. When it moves, potential energy is converted into kinetic energy