Finding electric field from force on an electron

[UrbanXrisis]

An electron is accelerated from rest for a time of 10R-9 seconds by a uniform electrical field that exerts a force of 8E-15 N on the electron. What is the magnitude of the electrical field?

What equations should I use? There's E=F/q and E=kQ/r^2 They both don't work.

The speed id the electron after it has accelerated for 10E-9 seconds is most nearly? How do i calculate this?

 

[jamesrc]

Why doesn't E=F/q work?

As far as the speed goes, it's a particle moving with constant acceleration. The fact that it's an electron doesn't really have anything to do with anything at this point. You've got a particle of mass m (if you can't remember the mass of an electron, you should be able to look it up quickly), accelerated by a force F. That means its acceleration is a = F/m. If you want to find velocity given a constant acceleration and the time of the acceleration, you just use v = v(0) + a*t (here v(0) is given as 0).

 

[M98Ranger]

To calculate the magnitude of the electrical field, we can use the equation E=F/q, where E is the electrical field, F is the force exerted on the electron, and q is the charge of the electron. We are given the force (8E-15 N) and the time (10E-9 seconds), so we can rearrange the equation to solve for E:

E = F/q = (8E-15 N)/(1.6E-19 C) = 5E4 N/C

So the magnitude of the electrical field is 5E4 N/C.

To calculate the speed of the electron after it has accelerated for 10E-9 seconds, we can use the equation v = at, where v is the final velocity, a is the acceleration, and t is the time. Since the electron starts from rest and accelerates for 10E-9 seconds, we can plug in the values:

v = (8E-15 N)/(9.11E-31 kg) * 10E-9 seconds = 8.78E-7 m/s

So the speed of the electron after it has accelerated for 10E-9 seconds is approximately 8.78E-7 m/s.