A long string with a charge of λ per unit length passes through an imaginary cube of edge a. The maximum flux of the electric field through the cube will be
Answer & explanation
Correct answer: option 4
The maximum length of the string which can fit into the cube is $\sqrt{3} a$, equal to its body diagonal. The total charge inside the cube is $\sqrt{3} a \lambda$, and hence the total flux through the cube is $\frac{\sqrt{3} a \lambda}{\varepsilon_0}$.
∴ (D)