Question

The two charges in the figure below are separated by d = 4.00 cm. (Let q1 = -14 nC and q2 = 27.5 nC.)

(a) Find the electric potential at point A.


(b) Find the electric potential at point B, which is halfway between the charges.

Answer 1

yeah, i listen to you tube and get electrocuted by my earphones in the right ear, twice, because static charge buildup and lost insulation cap on one earpiece. I 'll use better ones next time;
now to the matter at hand;

Answer 2

where is point A?

Answer 3

I will solve B)
I use the superposition principle of potentials. I calculate the potential in B first from q1, then from q2.

Answer 4

or in a formula
\[V = \left( 1 \over 4.\pi.\epsilon _{0} \right).\left( \left( q _{1} \over r _{1} \right) +\left( q _{2} \over r _{2} \right) \right)\]
gives
8,987.10^9 (-14.10^-9 C/2.10^-2 m + 27,5.10^-9 C /2.10^-2 m)
is
6066.6 Volt