Practice Problems
Coulomb's Law
Topics:
On this worksheet you will investigate properties of Coulomb's Law when multiple charges are present.
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omit
Question 1
Three point charges are placed on the x-axis as shown below. Find the net force on the 3.0 µC charge.
9.75 x 10
-1
N to the right
3.24 x 10
-1
N to the left
2.51 x 10
0
N to the right
1.86 x 10
0
N to the left
omit
Question 2
In the Bohr model of the hydrogen atom, an electron orbits a stationary proton at a radius of 0.53 Aº. How much kinetic energy does the electron possess?
1.99 x 10
-24
J
4.73 x 10
-40
J
9 x 10
22
J
2.16 x 10
-18
J
omit
Question 3
An initially neutral metal sphere is grounded through a switch, and a positively charged balloon is brought near it. After a few moments, the switch is opened and then the balloon is taken away. The sphere will now be
still neutral but polarized
still neutral
negatively charged
positively charged
omit
Question 4
Three charges are placed on three corners of a square as shown below. Each side of the square is 37 cm. What force would a +12 µC charge feel when placed at the vacant corner?
2.37 N
3.16 N
3.94 N
4.91 N
omit
Question 5
Which of the following statements is NOT true when comparing electrical forces and gravitational forces?
both forces can be attractive
both forces can be repulsive
when two electrons are in close proximity,
the gravitational force between them is smaller than the electrical force between them
omit
Question 6
Two charges are placed on the x-axis as shown on the diagram below. Where should a third charge -12 µC be placed if the force it experiences is to be zero?
between the charges, 0.2319 meters from 3 µC
0.6319 meters to the left of 3 µC
0.7839 meters to the left of 3 µC
between the charges, 0.1519 meters from 3 µC
omit
Question 7
A conducting sphere carries a charge of -12 µC. Which of the following statements is correct?
The sphere has gained 1.92 x 10
14
additional electrons and has an extra mass of
3.21 x 10
-13
kg.
The sphere has lost 1.92 x 10
14
electrons and a mass of
3.21 x 10
-13
kg.
The sphere has gained 7.5 x 10
13
additional electrons and has an extra mass of
6.83 x 10
-17
kg.
The sphere has lost 7.5 x 10
13
electrons and a mass of
6.83 x 10
-17
kg.
none of the other statements is correct
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