# q1=+6.25*10^-8 C. What is the potential difference when you go from point A to point B? They are all in a straight line. q1 is first, then?

point A, the point B. Going from left to right.

Between q1 and A: .150 m

Between A and B: .250 m

Unit= V

Round to the nearest thousandth if needed

### 3 Answers

- Steve4PhysicsLv 76 months agoBest Answer
Diagram: q1. .A. . . B

VA = kq/r = 8.99*10^9 * 6.25*10^-8 / 0.150

VB = kq/r = 8.99*10^9 * 6.25*10^-8 / 0.400

(because distance from q1 to B = 0.150 + 0.250 = 0.400m)

Potential difference from A to B is VB-VA:

= 8.99*10^9 * 6.25*10^-8 / 0.400 - 8.99*10^9 * 6.25*10^-8 / 0.150

= 8.99*10^9 * 6.25*10^-8 (1/0.400 - 1/0.150)

= -2341.146V

(The negative sign tells you the potential has dropped, going from A to B.)

It doesn't really make sense to give the answer to one thousandth of a volt because the values supplied are only 3 sig. figs. The best answer would be to use 3 sig. figs. giving - 2340V.

- Anonymous6 months ago
Va = k*6.25e-8/0.15 = 3745V

Vb = k*6.25e-8/0.40 = 1404V

3745 - 1404 = 2340.51 but we only have 3 s.d. so

Vab = 2340V

- Anonymous6 months ago
|Vb - Va| = work done by electric field to move q from a to b

if E = Eo (constant)

|Vb - Va| = Eo (xb - xa) = 100 Eo

if Eo = 10 V/m

|Vb - Va| = 1000 V

Also, the distances are 0.150m and 0.250m but the poster has not included the leading zeroes which makes it easy to mis-read, as you may have done.