A magnet brought near an old-fashioned TV screen such as in Figure 22.20 (TV sets with cathode ray tubes instead of LCD screens) severely distorts its picture by altering the path of the electrons that make its phosphors glow. (Don't try this at home, as it will permanently magnetize and ruin the TV.) To illustrate this, calculate the radius of curvature of the path of an electron having a velocity of 6.00 x 10⁷ m/s (corresponding to the accelerating voltage of about 10.0 kV used in some TVs) perpendicular to a magnetic field of strength B = 0.500 T (obtainable with permanent magnets).

Strategy

We can find the radius of curvature r directly from the equation r = mv/qB, since all other quantities in it are given or known.

Transcribed Image Text:

es B N S B