An accelerating voltage of 2.46 * 10^3 V is applied to an electron gun, producing a beam of electrons originally traveling horizontally north in vacuum toward the center of a viewing screen 34.0 cm away.

Question

What is the magnitude of the deflection on the screen caused by the Earth's gravitational field?

I am using this formula
v = squareroot(-2*q*V/m) to find speed and then B = mv/er for the magnitude

but they are asking the answer to be in meters...

Answer 1

Well, I have a problem with the second equation. The deflection of the particle traveling in a magnetic field is based on force

Force=m v B SinTheta where Theta is the angle between velocity and B.
http://www.ux1.eiu.edu/~cfadd/1360/29MagFlds/HmwkSol.html

But here, the velocity is North, which is almost parallel with the Earth's magnetic field, or zero force, and no deflection.
Now in reality, The Earths magnetic field is not exactly North, and depending with latitude, not exactly parallel with Earth's axis. So it is somewhat complicated the exact angle between v and North Magnetic.
I suspect you teacher wants you to assume zero force.

Answer 2

sir i read through the site so when i use force 0 how should i solve this question?

thank you

Answer 3

see my answer posted elsewhere