Question

Consider the following apparatus for measuring the charge per mass (q/m) ratio of the proton. This apparatus employs the same physics as in mass spectrometers. It consists of a pair of plates that accelerate a beam of protons starting from rest at the left-most plate to a speed of 1 x 10⁷ m/s, followed by a velocity selector set to only pass this speed, and a final set of deflector plates.

(a) The left side of the accelerator plate is ["neutrally", "negatively", "positively"]charged and the right side of the accelerator plate is                             [ ["negatively", "neutrally", "positively"]charged.

The potential difference between the accelerator plates is most nearly ["1.33e-32 V", "0.05 V", "522 kV", "3.2e-20 V"]

(c) In the velocity selector, the direction of the magnetic force on the proton is["Out of the screen", "Up", "Down", "Left", "Into the screen", "Right"]         .

(d) In the velocity selector, the direction of the electric force on the proton is ["Right", "Left", "Up", "Down", "Out of the screen", "Into the screen"]   

Continuing the previous question, the protons travel 30 cm between two deflector plates spaced by 15 cm with a potential difference of 100 kV and hit a detector screen:

(e) What is the distance of vertical deflection of the protons when they arrive at the screen? You may neglect gravity.

Answer 1