Answer to Question #182792 in Physics for Janusz

Question

The two charge points are held at the two vertices of the rectangle as shown in the figure. The sides of the pentagon are 5 cm and 15 cm. a) Determine the electric potential at the top of the rectangle marked with A. b) Find the potential difference between points B and A, ie. find VB - VA.

-5µC__ _ __ __ ___ __ ___ __ ___ _A

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B |___ __ ___ __ __ __ __ __ ___|+2µC

Answer 1

1)

$$V_A=9\cdot10^9\frac{-5\cdot10^{-6}}{0.15}+9\cdot10^9\frac{2\cdot10^{-6}}{0.05}=60000\ V$$

2)

$$V_B=9\cdot10^9\frac{-5\cdot10^{-6}}{0.05}+9\cdot10^9\frac{2\cdot10^{-6}}{0.15}=-780000\ V$$

$$V_B-V_A=-840000\ V$$