- #1
NotaPhysicsMan
- 146
- 0
Here's the question.
The drawing (attached) shows an electron entering the lower left side of a parallel plate capacitor and exiting at the upper right side. The inital speed of the electron is 7.00x 10^6m/s. The capacitor is 2.00cm long, and its plates are separated by 0.150cm. Assume that the electric field between the plates is uniform everywhere and find its magnitude.
Here's what I got.
Seems simple enough. I use E=q/(A Eo), where (permittivity of space) Eo=8.85x10^-12C^2/N.
Ok so I plug in the charge of an electron divided by the area of the rectangle and Eo. So 1.60x10^-19/((2.00cm/100 x 0.150cm/100)(8.85x10^-12)). I get something like 6.03x10^-8 N/C.
See, I didn't use the velocity they gave me, that's where I think the problem is, but I don't see where I could use it! Maybe to find acceleration using kinematics, nope not that...
Any ideas?
Thanks
The drawing (attached) shows an electron entering the lower left side of a parallel plate capacitor and exiting at the upper right side. The inital speed of the electron is 7.00x 10^6m/s. The capacitor is 2.00cm long, and its plates are separated by 0.150cm. Assume that the electric field between the plates is uniform everywhere and find its magnitude.
Here's what I got.
Seems simple enough. I use E=q/(A Eo), where (permittivity of space) Eo=8.85x10^-12C^2/N.
Ok so I plug in the charge of an electron divided by the area of the rectangle and Eo. So 1.60x10^-19/((2.00cm/100 x 0.150cm/100)(8.85x10^-12)). I get something like 6.03x10^-8 N/C.
See, I didn't use the velocity they gave me, that's where I think the problem is, but I don't see where I could use it! Maybe to find acceleration using kinematics, nope not that...
Any ideas?
Thanks