KCET2023PhysicsElectrostatics
A cubical Gaussian surface has side of length a=10 ~cm . Electric field lines are parallel to X -axis as shown in figure. The magnitudes of electric fields through surfaces A B C D and E F G H are 6 kNC ⁻¹ and 9 kNC ⁻¹ respectively. Then, the total charge enclosed by the cube is [Take, ₀=9 10⁻¹² Fm ⁻¹ ]
Options
- A-0.27 nC
- B1.35 nC
- C-1.35 nC
- D0.27 nC
Correct answer
D. 0.27 nC
Step-by-step solution
Total flux _E=E d s aligned & =9 k -6 k (10⁻² 10 )^2 & =3 10^3 10⁻²=30 NC ⁻¹ ~m ^2 aligned According to Gauss' law, q ₀ = _E aligned q_ endosed & =3 ₀ & =30 9 10⁻¹² C =270 10⁻⁹ 10⁻³ & =0.27 10⁻⁹ C =0.27 nC aligned