Q.

A line charge of length 'a'2 is kept at the center of an edge BC of a cube ABCDEFGH having edge length 'a' as shown in the figure. If the density of line charge is λ C per unit length, then the total electric flux through all the faces of the cube will be ______ (Take, ε0 as the free space permittivity)          [2025]

1 λa8ε0  
2 λa16ε0  
3 λa2ε0  
4 λa4ε0  

Ans.

(1)

Charge of the line charge =aλ2

Portion of wire inside cube =14

Total charge inside the cube, qen=14(aλ2)=λa8

  ϕ=qenε0=λa8ε0