Question

Figure shows variation of Coulomb force (F) acting between two point charges with `1/r^2`, r being the separation between the two charges (q₁, q₂) and (q₂, q₃). If q₂ is positive and least in magnitude, then the magnitudes of q₁, q₂ and q₃ are such that:

Options

• q₂ < q₃ < q₁

• q₃ < q₁ < q₂

• q₁ < q₂ < q₃

• q₂ < q₁ < q₃

Answer 1

q₂ < q₃ < q₁

Explanation:

Given q₂ is positive and least in magnitude.

From Coulomb’s Force, (F) = `1/(4 pi epsilon_0) (q_1q_2)/r^2`

Now, from the given graph F vs 1/r², the product of the magnitude of the charges will be the slope of the curve.

∵ tanθ₁ > tanθ₂

⇒ θ₁ > θ₂    ...[If the angle is very small]

⇒ q₁q₂ > q₂q₃

⇒ q₁ > q₃

And q₂ has the least magnitude.

Hemce, q₁ > q₃ > q₂