Question Detail
Question
Determine the electric flux emerging from a circular surface radius 0.025m if the electric field strength is 100V/m and the field lines makes an angle of 30° with the surface.
Correct Answer
Option A is the correct answer.
Detailed Explanation
Electric flux (Φ) is given by Φ = E * A * cos(θ), where E is the electric field strength, A is the area of the surface, and θ is the angle between the electric field lines and the normal to the surface.Given: E = 100 V/m, radius r = 0.025 m.Area A = π * r^2 = π * (0.025 m)^2 = π * 0.000625 m^2 ≈ 0.001963 m^2.The angle with the surface is 30°. Therefore, the angle with the normal to the surface is θ = 90° - 30° = 60°.Φ = 100 V/m * 0.001963 m^2 * cos(60°)Φ = 100 * 0.001963 * 0.5Φ = 0.09815 Nm²/C.
Hint
Be careful with the angle in the electric flux formula; it's the angle with the *surface normal*, not the surface itself. Don't confuse radius with area squared in the question text.