Question

(30-Q2a) shows an imaginary cube of edge L/2. A uniformly charged rod of length L moves towards the left at a small but constant speed ν. At t = 0, the left end just touches the centre of the face of the cube opposite it. Which of the graphs shown in the figure (30-Q2b) represents the flux of the electric field through the cube as the rod goes through it?
FigureFigure

Answer 1

Graph D represents the electric field’s flux through the cube as the road goes through it.

Explanation:

Gauss’ law says,  

Electric flux = E.ds = q/ϵ0,

Where,  

ϵ0 = vacuum’s electric permittivity.

q = surface enclosed total charge,

• At t=0, the center of the cube’s face is touched by the left end and this is opposite to the left face.
• First, inside the cube, the charge is zero. Hence, from the origin, the graph starts. The graph is accomplished when the straight line becomes zero until the flux.