Phsx 2220 - Homework #3
25-1. The electric potential difference between the ground and a cloud in
a particular thunderstorm is 1.2 x 109 V. What is the magnitude of
the change in the electric potential energy (in multiples of the
electron-volt) of an electron that moves between the ground and the
cloud?
25-2. When an electron moves from A to B along an
electric field line in the figure at right,
the electric field does 3.94 x 10-19 J of work
on it. What are the electric potential
differences (a) VB - VA, (b) VC - VA, and
(c) VC - VB?
25-3. An infinite nonconducting sheet has a surface charge density
σ = 0.10 µC/m2 on one side. How far apart are equipotential
surfaces whose potentials differ by 50 V?
25-4. Consider a point charge q = 1.0 µC, point A at
distance d1 = 2.0 m from q, and point B at
distance d2 = 1.0 m. (a) If these points are
diametrically opposite each other, as in the
top figure at right, what is the electric
potential difference VA - VB? (b) What is that
electric potential difference if points A and
B are located as in the bottom figure at
right?
25-5. In the figure at right, what is the net
potential at point P due to the four point
charges, if V = 0 at infinity?
25-6. The figure at right shows a ring of outer
radius R and inner radius r = 0.200 R; the
ring has a uniform surface charge density σ.
With V = 0 at infinity, find an expression for
the electric potential at point P on the
central axis of the ring, at a distance
z = 2.00 R from the center of the ring.
