In the rectangle of the figure the sides have lengths 6.96 cm and 17.6 cm, q_1 =
ID: 1412453 • Letter: I
Question
In the rectangle of the figure the sides have lengths 6.96 cm and 17.6 cm, q_1 = -4.80 mu C, and q_2 = +2.17 mu C. With V = 0 at infinity, what is the electric potential at (a) corner A and (b) corner B? (c) How much work is required to move a charge q_3 = + 3.68 mu C from B to A along a diagonal of the rectangle? (d) Does this work increase or decrease the electric potential energy of the three-charge system? Is more, less, or the same work required if q_3 is moved along a path that is (e) inside the rectangle but not on a diagonal and (f) outside the rectangle?Explanation / Answer
ANSWER
a)
CA = BD = 0.176 m and AD = BC = 0.0696 m
At Corner A :
Va = k q1 /CA + k q2 / AD = (9 x 109) (- 4.8 x 10-6 / 0.176 + 2.17 x 10-6 / 0.0696) = 3.51 x 104 volts
b)
At Corner B :
Vb = k q1 /BC + k q2 / BD = (9 x 109) (- 4.8 x 10-6 / 0.0696 + 2.17 x 10-6 / 0.176) = - 5.09 x 105 volts
c)
Potential difference between B and A, V = (3.51 x 104) - (- 5.09 x 105) = 5.44 x 105 volts
q3 = charge = 3.68 x 10-6
Work done = q3 V = (3.68 x 10-6) (5.44 x 105 ) = 2.00192 J
d)
it increases the potential energy of the system.
e)
work done remain same as work done only depends on initial and final points and not on the path taken.
f)
work done remain same as work done only depends on initial and final points and not on the path taken.
Regards!!!