Question

Electric field due to infinite, straight uniformly charged wire varies with distance ‘r’ as

• A. r
• B. \(\frac{1}{r}\)
• C. \(\frac{1}{r^2}\)
• D. r²

Answer 1

The Correct Option is B

The electric field due to an infinitely long, straight, uniformly charged wire is given by:

$E = \frac{\lambda}{2\pi\epsilon_0 r}$

where:

• $\lambda$ is the linear charge density (charge per unit length),
• $\epsilon_0$ is the permittivity of free space, and
• $r$ is the perpendicular distance from the wire.

Since $\lambda$ and $\epsilon_0$ are constants, the electric field $E$ is inversely proportional to the distance $r$: $E \propto \frac{1}{r}$.

The correct answer is (B) $\frac{1}{r}$.