A charge q is surrounded by a closed surface consisting of an inverted cone of height h and base radius R, together with a hemisphere of radius R as shown. The electric flux through the conical surface is nq/(6ε₀). Find n.

Question

G1 Physics · Accepted Answer

The charge q lies at the common centre of the hemispherical part. The flux through the hemisphere is q/(2ε₀), because a hemisphere subtends half of the full solid angle 4π. The total flux through the complete closed surface is q/ε₀. Therefore flux through the conical surface = q/ε₀ - q/(2ε₀) = q/(2ε₀) = 3q/(6ε₀). Hence n = 3.