Two parallel large thin metal sheets have equal charge densities of \( 5.31\times10^{-11}\,\mathrm{C\,m^{-2}} \) of opposite signs. If the permittivity of free space is equal to \( 8.85\times10^{-12}\,\mathrm{C^{2}\,N^{-1}\,m^{-2}} \), the electric field between these sheets will be
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 6\,\mathrm{N\,C^{-1}} \)
Each large sheet produces a uniform field \( \sigma/2\varepsilon_0 \) on both sides. Between two oppositely charged sheets the two fields point the same way and add; outside they cancel.
\( \displaystyle E = \frac{\sigma}{2\varepsilon_0} + \frac{\sigma}{2\varepsilon_0} = \frac{\sigma}{\varepsilon_0} \)
\( \displaystyle E = \frac{5.31\times10^{-11}\,\mathrm{C\,m^{-2}}}{8.85\times10^{-12}\,\mathrm{C^{2}\,N^{-1}\,m^{-2}}} = 6.0\,\mathrm{N\,C^{-1}} \)
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 – …
