• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Help please :) force on an electron in an electric field (1 Viewer)

nancylime

Member
Joined
Aug 19, 2014
Messages
76
Gender
Female
HSC
2015
I'm not sure how to approach this question - I tried using F=qvBSin(theta) but I can't work out what the magnetic field strength is? does anyone know how to do it?

An electron moving at 4.0x103 m/s enters the electric field between two metal plates separated by 10cm with a potential difference of 50V across the plates. What is the force on the electron?
 

Crisium

Pew Pew
Joined
Feb 17, 2014
Messages
2,009
Location
Australia
Gender
Male
HSC
2015
E = V / d

Where E = Electric Field Strength

E = 50 / 0.1

Since its between two electric plates the potential difference between them is fixed + Don't forget to convert cm to m

E = 500 V/m

Therefore

F = (-1.602x10^-19) x 500

Since it's force in an ELECTRIC FIELD make sure you use the correct formula; the one you were using is force in a MAGNETIC FIELD and remember to add the direction of the vector)
 
Last edited:

Crisium

Pew Pew
Joined
Feb 17, 2014
Messages
2,009
Location
Australia
Gender
Male
HSC
2015
The formula I used for the Force on an electric field is a rearranged formula

It's found on the data sheet as E = F / q

So F = Eq
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top