Q 59

Four 2.0-µC point are at the corners of a rectangle with sides of length 3.0 cm and 4.0 cm.What is the electric potential (relative to infinity)at the midpoint of the rectangle? (k = 1/4πε_{0} = 9.0 × 10^{9} N ∙ m^{2}/C^{2})
A)1.3 MV
B)2.9 MV
C)3.5 MV
D)7.8 MV

Q 60

A square is 1.0 m on a side.Point charges of +4.0 μC are placed in two diagonally opposite corners.In the other two corners are placed charges of +3.0 μC and -3.0 μC.What is the potential (relative to infinity)at the midpoint of the square? (k = 1/4πε_{0} = 9.0 × 10^{9} N ∙ m^{2}/C^{2})
A)1.0 × 10^{4} V
B)1.0 × 10^{5} V
C)1.0 × 10^{6} V
D)0 V
E)infinite

Q 61

Two 5.0-µC point charges are 12 cm apart.What is the electric potential (relative to infinity)of this combination at the point where the electric field due to these charges is zero?
A)0.75 MV
B)1.5 MV
C)0.0 MV
D)25 MV
E)12.5 MV