The diagram shows two point charges A and B. The magnitude of each charge and di
ID: 2008469 • Letter: T
Question
The diagram shows two point charges A and B. The magnitude of each charge and distances between them is given.
a) What is the magnitude and direction of the force which sphere B exerts on sphere A?
b) Determine the magnitude and direction of the electric field at Point A.
c) At what point (measured from A) would the field intensity be zero?
d) How much force would be created on a 2C test charge placed at point P.
e) What is the eletrical potential at point P.
f) If the 2C test charge is now to be moved to point X, where the elecrical potential is 2x105 volts, how much work must be done?
Explanation / Answer
qA = 10 C, qB = 6 C, r = 0.60 m,
a) What is the magnitude and direction of the force which sphere B exerts on sphere A?
F = k*qA*qB/r2 = 1.5 N, (to the left)
b) Determine the magnitude and direction of the electric field at Point A.
E = F/qA = 1.5*105 N/C (to the left)
c) At what point (measured from A) would the field intensity be zero?
qA/x2 = qB/(r - x)2
(r - x)/x = (qB/qA) = 0.6
r/x - 1 = 0.6
x = r/(1 + 0.6) = 0.338 m
d) How much force would be created on a q = 2 C test charge placed at point P.
F = kq*qA/(r/2)2- kq*qB/(r/2)2 = 0.8 N
e) What is the eletrical potential at point P.
Up = kqA/(r/2) + kqB/(r/2) = 4.8*105 V
f) If the 2C test charge is now to be moved to point X, where the elecrical potential is Ux = 2 x 105 volts, how much work must be done?
2 C * (Ux - Up) = -0.56 J