The flux of the electric field \( \vec{E}=2\times10^{3}\,\hat{\imath}\ \mathrm{N/C} \) through a square of 10 cm, on a side whose plane is parallel to the xy plane is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 0
The flux through a plane area is \( \phi = \vec{E}\cdot\vec{A} = EA\cos\theta \), where the area vector \( \vec{A} \) is normal to the surface. A square lying in the xy plane has its normal along \( \hat{k} \).
\( \phi = (2\times10^{3}\,\hat{\imath})\cdot(A\,\hat{k}) = 0 \)
The field is along x, parallel to the surface, so \( \theta = 90^\circ \) and no field line crosses the square.
Note: NTA picked this question from an NCERT (2026-27) exercise and changed the figures. Do not ignore NCERT while practising numericals.
NCERT (2026-27):
Exercises – …
