Questions on Electric Fields and Coulombs law
You have two do to G questions and/or two VG questions on this sheet until Wednesday
week 16
1. What is the magnitude and direction of the electric force on an electron
in a uniform electric filed of strength 3500N/C that points due east?
G
2. A proton is released in a uniform electric field and it experiences an electric
force of 3.2 · 10−14 N toward the south. What are the magnitude and
direction of the electric field?
G
3. An electron is released from rest in a uniform electric field and accelerates
to the north at a rate of 125m/s2 . What is the magnitude and direction
of the electric field?
VG
4. Two parallel plates are charged so that the upper plate has a positive
charge and the lower plate has a negative charge.
(a) What is the direction of the electric field between the plates?
G
A drop of oil is made to hover between the two plates.The mass of the
drop is 0.33 · 10−12 g.
(b) Is the charge of the drop of oil positive or negative?
G
(c) What is the magnitude of the charge of the drop of oil assuming that
the field strength between the plates is 2.0kN/C
VG
5. How does the force between two charged balls change assuming that
G
(a) The charges of both balls doubles.
(b) The distance between the balls doubles?
6. Two charged Ping-Pong balls separated by a distance of 1.5m exert a force
of 0.0200N on each other. What will be the force if the objects are brought
closer, to a separation of only 30.0cm?
Mass of electron
Mass of proton
Charge of electron
Charge of proton
1
9.1 · 10−31 kg
1.67 · 10−27 kg
−1.6 · 10−19 C
+1.6 · 10−19 C
VG