A horizontally projected beam of protons travels at 55 km/s into the space between two horizontal, parallel plates. The plates are separated by 7.4 cm, and they are 12 cm long. The uniform electric field between the plates is 7.2 V/m upward. If the beam enters the region at a height of 3.7 cm above the lower plate, at what height above the lower plate does the beam exit the region? The proton mass is 1.67 × 10^-27 kg. A) 4.4 cm B) 3.9 cm C) 5.1 cm D) 2.3 cm

Question

Quizplus · Accepted Answer

The vertical acceleration of the protons due to the electric field can be calculated using F = ma = qE, where q is the charge of a proton (1.6 × 10^-19 C). The time to travel the length of the plates is t = 12 cm / 55,000 cm/s. Using the kinematic equation for vertical motion, the vertical displacement can be calculated and added to the initial height to find the exit height.

A Horizontally Projected Beam of Protons Travels at 55 Km/s