JEE Main Physics: Coulomb's law Practice Questions
15 free multiple-choice questions on Coulomb's law (Electricity and Magnetism) for JEE Main Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more JEE Main questions in the app →Q1. Coulomb's law states that the electrostatic force between two charges is proportional to the product of the charges and inversely proportional to the:
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Correct answer: A — Square of the distance between them
Coulomb's law is mathematically defined as F = k (|q₁ q₂|)/r². The force is directly proportional to the product of the charges (q₁ q₂) and inversely proportional to the square of the distance (r²).
Q2. The electrostatic force between two like charges is always:
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Correct answer: B — Repulsive
Like charges attract each other, and unlike charges repel each other. Since the charges are the same (like charges), the force exerted between them is repulsive.
Q3. Coulomb's constant (k) in the equation of Coulomb's law has what physical significance?
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Correct answer: B — It is the proportionality constant relating force to the product of charges and distance
Coulomb's constant (k = 1/4πε₀) is the proportionality constant that relates the electrostatic force between two charges to the product of the charges and the inverse square of the distance.
Q4. Two point charges q₁ and q₂ are separated by a distance r. If the magnitude of the charges is increased by a factor of 3, the new electrostatic force will be:
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Correct answer: C — 9 times
The electrostatic force is directly proportional to the product of the charges (F ∝ q₁ q₂). If both charges are multiplied by 3, the new force F' = k ((3q₁)(3q₂))/r² = 9 ( k (q₁ q₂)/r² ) = 9F.
Q5. Two charges, q₁ = +2 μC and q₂ = -3 μC, are separated by a distance r. The force of interaction between them will be:
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Correct answer: D — Attractive
Since the charges have opposite signs (one positive and one negative), they exert an attractive force on each other, according to Coulomb's law.
Q6. The relationship derived from Coulomb's law concerning the force between two charges is a direct proportionality to the product of the magnitudes of the charges and an inverse proportionality to the:
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Correct answer: B — Product of the charges
The magnitude of the electrostatic force is proportional to the product of the magnitudes of the charges (|q₁ q₂|) and inversely proportional to the square of the distance between them (r²).
Q7. If the charges are separated by twice the distance, the magnitude of the electrostatic force will be:
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Correct answer: A — One-fourth
Since the force is inversely proportional to the square of the distance (F ∝ 1/r²), if the distance r is doubled, the force F becomes F / (2²) = F/4. The force is reduced to one-fourth of the original value.
Q8. Coulomb's law describes the force between two point charges. The force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. This relationship is mathematically expressed by:
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Correct answer: C — F = k * q1 * q2 / r
Coulomb's Law states that the force (F) is proportional to the product of the charges (q1*q2) and inversely proportional to the square of the distance (r²). The formula is F = k * (q1*q2) / r².
Q9. If the distance between two point charges is doubled, the electrostatic force of attraction between them will become:
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Correct answer: D — one-fourth
Since the force is inversely proportional to the square of the distance (F ∝ 1/r²), if the distance (r) is doubled (2r), the new force will be F' ∝ 1/(2r)² = 1/(4r²). Thus, the force becomes one-fourth of the original force.
Q10. If the magnitude of two charges is kept constant, what happens to the electrostatic force if the distance between them is halved?
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Correct answer: A — It becomes half
Since force is inversely proportional to the square of the distance (F ∝ 1/r²), if the distance r is halved (r/2), the new force F' will be F' = k (q₁ q₂)/((r/2)²) = k (q₁ q₂)/(r²/4) = 4 ( k (q₁ q₂)/r² ) = 4F.
Q11. The electrostatic force between two charges is attractive. This occurs when the charges are:
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Correct answer: A — one positive and one negative
Coulomb's law dictates that like charges repel each other, and opposite charges attract each other. Attraction occurs only when the charges have opposite signs.
Q12. According to Coulomb's law, if the distance between two point charges is doubled, the electrostatic force between them will change by a factor of:
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Correct answer: A — 1/4
Coulomb's law states that the force is inversely proportional to the square of the distance (F ∝ 1/r²). If r is doubled (2r), the new force F' will be F' = k (q₁ q₂)/((2r)²) = k (q₁ q₂)/4r² = 1/4 ( k (q₁ q₂)/r² ) = F/4.
Q13. Which of the following statements correctly describes the nature of the force described by Coulomb's law?
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Correct answer: A — The force depends on the relative signs of the charges.
Coulomb's law describes the interaction (both attractive and repulsive) between charges based on their signs and the distance between them. The force is attractive for opposite charges and repulsive for like charges.
Q14. The magnitude of the electrostatic force between two charges is directly proportional to the product of the magnitudes of the charges. If the magnitude of one charge is tripled while keeping the other charge constant, the force of interaction will:
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Correct answer: D — be tripled
Since F ∝ q₁ q₂, if q₁ is tripled, the force F is also tripled, assuming q₂ remains constant.
Q15. The electrostatic force between two point charges is inversely proportional to the square of the distance separating them. This relationship is described by:
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Correct answer: C — F ∝ 1/r²
Coulomb's Law states that the force between two charges is inversely proportional to the square of the distance (r) between them, meaning F ∝ 1/r².
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