Answer:
A) V = 55.57 V
B) E = -1.61 x 10^(-7)J
C) Negative sign means that positive work must be done to separate the charges (bring them up to a state of zero potential energy)
Explanation:
A) Electric potential is given by the formula;
V = KQ/d
Since there are two charges and we are looking for the electric potential at a point midway through them, we now have;
V = kQ1/0.5d + kQ2/0.5d
This can be arranged as;
V = (k/0.5d)(Q1 + Q2)
Where;
k is coulombs constant and has a value of 8.99 x 10^(9) N.m²/C²
d = 55 cm = 0.55m
Q1 = +4.10 nC = 4.1 x 10^(-9) C
Q2 = −2.40 nC = -2.4 x 10^(-9) C
Thus;
V = (8.99 x 10^(9))/(0.5 x 0.55)[4.1 x 10^(-9) - 2.4 x 10^(-9)]
V = 55.57 V
B) The formula for the potential energy of the pair of charges is;
E = kQ1•Q2/d
Thus, E = [(8.99 x 10^(9)) * 4.1 x 10^(-9) * -2.4 x 10^(-9)]/0.55
E = -160.8 x 10^(-9)
Or
E = -1.61 x 10^(-7)J
C) Negative sign means that positive work must be done to separate the charges (bring them up to a state of zero potential energy)
