Question

A charge q is placed at the centre of a cube of side l. What is the electric flux passing through two opposite faces of the cube? [CBSE (AI) 2012]

January 13, 2024

Answer

By symmetry, the flux through each of the six faces of the cube will be the same when charge q is placed at its centre.

∴ φ_E = ${1\over 6}{Q\over \varepsilon_0 }$

Thus, electric flux passing through two opposite faces of the cube = 2× ${1\over 6}{Q\over \varepsilon_0 }$

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