Television Physics Problem.....?

Question

If a television set were laid on its back, wold electrons be able to move upward against the force of gravity?
What potential difference, acting over a distance of 3 cm would be needed to balance the downward force of gravity so that an electron would remain stationary? Assume that the electric field is uniform.

Answer 1

yes it would because the force of the electric field is a lot stronger than the force of gravity over short distances (such as a TV)

eqns needed:
F = m*g
F = q*E
V = E*d

known/given:
q=1.6*10^-1 C
m=9.11*10^-31 kg
g=9.8 m/s^2
d = 3 cm = .03 m

Solution:
we know two manifestations of the force equation as well as the potential difference (voltage) equation. so plug everything and solve for V. You should get the following eqn:

V = (m*g*d)/q

all of those are already known, so just plug n' chug. what's interesting to note is that you don't ever need to know what the magnitude of the electric field is !! (see answer as to why)

ANSWER: 1.676*10^-12 Volts (very little voltage required to stagnate an electron, which proves exactly why gravity is so weak with respect to the electric field!)

FYI: in order to make an electron stationary using your typical AA battery (which is 1.5 volts), you would need a distance of 26,500,000,000 meters between the plates in order to do so (one plate on Earth and the other 1/3 distance between Earth and Mars!!!)

Answer 2

Electrons would have no problem moving upwards in a TV. People who work in particle physics don't even include gravity on their calculations because it's so weak. Its mas is only 9 x 10^ -31 kg.

Answer 3

While the electrons will still hit the screen, the colors would be mucked up. The alignment of the electron guns account for the magnetic field of the Earth.