Adding the forces from several charges
"Adding the forces from several charges" is a free, interactive Class 12 Physics simulation for NEET and JEE, built on the NCERT section "Forces between multiple charges" in Electric Charges and Fields. Coulomb forces on a test charge from up to three fixed charges, drawn as vectors and added tip to tail or by components into the resultant. JEE Main asked 39 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Forces between multiple charges in Electric Charges and Fields. Change the values and watch what happens.
What it shows
NCERT §1.6
Coulomb forces on a test charge from up to three fixed charges, drawn as vectors and added tip to tail or by components into the resultant.
Controls
3 to try
- Dragpositions of q1, q2, q3 and the test charge
- Slidereach charge −5 to +5 μC
- Togglecomponents / parallelogram
Try this
With +4 μC and +1 μC 30 cm apart, place the test charge where the net force is zero (10 cm from the +1 μC)
Common mistake
Adding the magnitudes of forces from several charges.
In JEE Main
42 shifts analysed
39 questions from Electric Charges and Fields across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT §1.6
- Principle of superposition: the force on a charge due to several others is the vector sum of the forces each would exert alone.
- The force between any two charges is unaffected by the presence of other charges; each pair obeys Coulomb's law as if it were alone.
- F₁ = F₁₂ + F₁₃ + … + F₁ₙ, added by the parallelogram (or component) method, never by adding magnitudes.
- All of electrostatics follows from two ideas: Coulomb's law and the superposition principle.
- Symmetry often gives the answer: equal charges at the corners of an equilateral triangle exert zero net force on a charge at its centroid.
- For any set of charges held only by their mutual forces, the forces on all of them add to zero, because Coulomb forces come in equal and opposite pairs.
Questions
4 answers
- What does the "Adding the forces from several charges" simulation show?
- Coulomb forces on a test charge from up to three fixed charges, drawn as vectors and added tip to tail or by components into the resultant.
- What mistake does the "Adding the forces from several charges" simulation fix?
- A common mistake it clears up: adding the magnitudes of forces from several charges.
- Does JEE Main ask questions from Electric Charges and Fields?
- Yes. JEE Main asked 39 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Forces between multiple charges" in Electric Charges and Fields (Class 12 Physics).
Embed this simulation
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