SP212/3321&5521
Chapter 22 - Worksheet #1
Question 1: Two opposite charges (one positive and one negative) are placed on a line. The charge
on the right is three times large (in magnitude) than the charge on the left. Where along this line
is the electric field zero (other than infinitely far away)?
ql
qr
(A) Between the two charges
(B) To the right of the charge on the right
(C) To the left of the charge on the left
(D) Nowhere
(E) Not enough information - we need to know which charge is positive
Question 2: Two point charges (−3.5 µC and −4.0 µC) are placed as shown, 0.60 m apart. Point P
is between the two charges, 0.40 m away from the −3.5 µC charge. What is the magnitude of the
electric field at point P ? What direction does it point?
0.40 m
0.20 m
P
−4.0 µC
−3.5 µC
Question 3: Two point charges (−3.0 µC and +5.0 µC) are placed as shown. What is the electric
field at point P in vector form? What is its magnitude?
y
−3.0 µC
1.50 m
P
0.90 m
x
5.0 µC
SP212/3321&5521
Chapter 22 - Worksheet #1
Question 4: Two point charges (−3.0 µC and +6.0 µC) are placed on the x-axis, with the −3.0 µC
charge located at x=0 and the +6.0 µC charge located at x=1.5 m. At what position on the x-axis
is the net electric field zero?
y
−3.0 µC
x
6.0 µC
Question 5: Two point charges (+5.0 µC and −5.0 µC) are located 0.75 m apart. What is the
magnitude of the electric field at point P , which is 0.75 m away from each of the two charges?
(Point P and the two charges form an equilateral triangle.)
P
5m
0.7
60◦
+
+5.0 µC
−
−5.0 µC
Question 6: Two point charges, of +4.0 nC and −4.0 nC, are separated by a distance of 3.5 µm.
What is the magnitude of the electric field at a point that is a distance of 0.25 m away from the
center of these two charges and along the axis connecting them?