The electric field is E = (2,4,6)×10³ N/C. The electric flux through a rectangular surface parallel to the x-z plane is 6.0 N·m²/C. Find the area of the surface in cm².
Physics · Electrostatics · electric flux and gauss law
JEE Mains 2025 7 April Evening Shift

Question

The electric field is E = (2,4,6)×10³ N/C. The electric flux through a rectangular surface parallel to the x-z plane is 6.0 N·m²/C. Find the area of the surface in cm².

G1 Physics · Accepted Answer

A surface parallel to the x-z plane has its area vector along the y-direction. Therefore only E y E_y E y ​ contributes to flux. E y E_y E y ​ = 4×10³ N/C. Electric flux: Φ = E·A = E y E_y E y ​ A. Thus, 6.0 = (4×10³)A. Hence, A = 6/(4×10³) = 1.5×10⁻³ m². Convert to cm²: 1 m² = 10⁴ cm². Therefore, A = 1.5×10⁻³×10⁴ = 15 cm². Answer: 15.