• Support PF! Buy your school textbooks, materials and every day products Here!

Help with determining distance where electric potential is 0

  • #1
40
0
Member advised to use the homework template for posts in the homework sections of PF.
Question states 'Determine the distance from the +4.0nC charge to the point, along the straight line between the charges, where the electric potential is zero.'

upload_2016-5-29_16-5-50.png


This is as far as i've got: so I've used V=Q/4pi(epsilon0)r and then set it so V1+V2=0 (to find the point where the resultant electric potential is zero). Then the 4pi(epsilon0) can just be ignored as it is a constant, therefore V1=Q1/R1 and then V2=Q2/R2 therefore Q1/R1 + Q2/R2 = 0 so then (substituting in the values), 4x10^-9/r - 8x10^-9/ (80x10^-3) -r = 0 AND now I'm not sure where to go from this point

Thank you for any help
 

Answers and Replies

  • #2
Ssnow
Gold Member
509
149
do the sum between fractions and solve the equation in ##r## ...
 
  • #3
40
0
do the sum between fractions and solve the equation in ##r## ...
yeah thats the bit I cant seem to do my answer keeps coming out at 7000
 
  • #4
40
0
do the sum between fractions and solve the equation in ##r## ...
No worries I've got it now thanks!
 

Related Threads on Help with determining distance where electric potential is 0

Replies
1
Views
2K
Replies
4
Views
5K
Replies
19
Views
6K
Replies
7
Views
6K
Replies
40
Views
18K
Replies
4
Views
2K
Replies
8
Views
1K
Replies
1
Views
969
  • Last Post
Replies
4
Views
978
Top