Question

What is the electric potential 12 cm away from a charge of –5.2 × 10^–6C?

–3.3 × 10^6
–3.9 × 10^5
–3.9 × 10^3
–3.3 × 10^2

Answer 1

The equation for electric potential of a point charge is:

V=(k*q)/r where k=9*10^11 N m²/C², q is the charge and r is the distance from the charge to the point in which we are calculating the potential.

q=-5.2*10^-6 C
r=12 cm = 0.12 m

Now we plug in the numbers and get:

V=-3.9*10^5 Volts, so the correct answer is the second one.