Grade 11 · Science · Physics

11th grade Coulomb's law: the force between charges worksheet

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Coulomb's law: the force between charges

Grade 11 Science Worksheet - Building Confidence

NameDate

Circle the best answer, or write your answer on the line.

Two charged spheres push on each other with 48 mN. If the distance between their centers becomes 2 times as large, what is the force, Ari?
Two charged spheres push on each other with 90 mN. If the distance between their centers becomes 3 times as large, what is the force, Bo?
Two charged spheres push on each other with 80 mN. If the distance between their centers becomes 4 times as large, what is the force, Esme?
Read this first
Use this
Field-line diagram (example data):
4.
In the diagram, do the two spheres attract or repel, Jun?
- Neither, since the charges cancel
- They repel
- They attract
5.
In the diagram, how do the forces on the two spheres compare, Kira?
Use the picture in question 4.
- They are equal and opposite
- The − sphere feels more
- The + sphere feels more
6.
One of two charges doubles at the same distance. What happens to the force between them, Milo?
- It halves
- It is 4 times as big
- It doubles
7.
The distance between two charges doubles. What happens to the force, Noah?
- It doubles
- It halves
- It drops to one-quarter
8.
The distance between two charges halves. What happens to the force, Pia?
- It is 4 times as big
- It halves
- It doubles
9.
Two balloons both carry negative charge. Do they attract or repel, Ren?
- Attract
- Repel
- Neither
10.
Two spheres both carry positive charge. Do they attract or repel, Zee?
- Attract, since positive charges pull
- Neither, since positives are neutral
- Repel

Coulomb's law: the force between charges. Every version has 10 questions, and the answer key prints on the second page.

I can use F = kq₁q₂ ÷ r² with k = 8.9875 × 10⁹ N·m²/C², with charges in nC, distances in cm and forces in mN.
I can scale forces. Each charge counts once, while distance counts squared: twice as far gives one-quarter, and half as far gives 4 times. I can find the distance that gives a chosen force.
I can say that like charges repel and unlike attract, with equal and opposite forces. I can add forces from neighbors in a line.
I can compare Coulomb's law with gravity: both are inverse squares, but only electric forces repel, and electric forces are far stronger.

Standard: HS-PS2-4

Coulomb's law: F = kq₁q₂ ÷ r², the force between two charges

k: Coulomb's constant: 8.9875 × 10⁹ N·m²/C²

inverse square: The force falls as 1 ÷ distance²

nanocoulomb (nC): 10⁻⁹ coulombs, a typical charge for a rubbed balloon

net force: The total of all forces on an object, with directions

Your child divided by the distance factor, not its square. Coulomb's law is an inverse square: twice as far, one-quarter the force.

Your child did not square the distance. F = kq₁q₂ ÷ r².

Your child left out the square root. Rearranging F = kq₁q₂ ÷ r² gives r = √(kq₁q₂ ÷ F).

What is the most common mistake with coulomb's law: the force between charges?

Your child divided by the distance factor, not its square. Coulomb's law is an inverse square: twice as far, one-quarter the force.

Are these 11th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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