A charge Q is placed at the corner of a cube. The electric flux linked with this cube is-
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Q/(8ε0)
By Gauss’s law, a closed surface around Q carries a flux of \( Q/\varepsilon_0 \). A charge at a corner can be surrounded completely by 8 identical cubes meeting at that corner. By symmetry each cube receives an equal share of the total flux.
\( \displaystyle \phi_{\mathrm{total}} = \frac{Q}{\varepsilon_0} \)
\( \displaystyle \phi_{\mathrm{cube}} = \frac{1}{8} \times \frac{Q}{\varepsilon_0} = \frac{Q}{8\varepsilon_0} \)
Note: This question is from the NCERT Exemplar. NTA sets numerical questions from the Exemplar too, so do not ignore it while practising numericals.
NCERT Exemplar:
Electric Charges and Fields – …
