Problem 62 - A Complete Resource Book in Physics for JEE Main

Question

Coulomb's law is applicable to, (A) Point charges (B) Spherical charges (C) Like charges (D) All of these

Step-by-Step Solution

Answer

The correct answer is (D) All of these, as Coulomb's law is applicable to point charges, spherical charges, and like charges.

Step 1: Defining Coulomb's Law

Coulomb's law describes the electrostatic force of attraction or repulsion between two charged particles. The force between two point charges is given by the formula: \(F = k \cdot \frac{q_1 \cdot q_2}{r^2}\) where: - F is the electrostatic force, - k is the electrostatic constant (≈ 8.988 x 10^9 Nm^2/C^2), - q1 and q2 are the magnitudes of the point charges, - r is the distance between the point charges. Now, let's evaluate each option:

Step 2: (A) Point charges

Point charges are charges with zero dimensions, which means that their charge is concentrated at a single point in space. As Coulomb's law formula involves the charges q1 and q2 and the distance r between these charges, it is applicable to point charges.

Step 3: (B) Spherical charges

Spherical charges are charges distributed on the surface of a sphere. When dealing with two spheres with uniformly distributed charges on their surfaces, we can consider the charges on each sphere to be concentrated at their center. Therefore, Coulomb's law is applicable to spherical charges.

Step 4: (C) Like charges

Like charges are charges with the same sign, either both positive or both negative. The formula of Coulomb's law implies that like charges repel each other (positive x positive = positive, negative x negative = positive), while opposite charges attract each other (positive x negative = negative). Thus, Coulomb's law is applicable to like charges too.

Step 5: (D) Conclusion

Since Coulomb's law is applicable to point charges, spherical charges, and like charges, the correct answer is (D) All of these.