Question

44. Consider a uniform electric field E = 3x10î N/C. What
is the flux of this field through a square of 10 cm on a side
whose plane is parallel to the y- z plane?
(b) 20 NC- m?
(d) 40 NC-1 m
(a) 10 NC-'m
(c) 30 NC-'m​

Answer 1

answer:

(c) 30 NC-'m

explanation:

(a) Electric field intensity,

E =3×10^3 N/C

Magnitude of electric field intensity, ∣E∣=3×10^3 N/C

Side of the square, s=10cm=0.1m

Area of the square, A=s^2 =0.01m^2

The plane of the square is parallel to the y-z plane. Hence, angle between the unit vector normal to the plane and electric field, θ=0°

Flux (ϕ) through the plane is given by the relation,

ϕ=∣E∣Acosθ =3×10^3 ×0.01×cos0°=30Nm^2 /C

(b)Plane makes an angle of 60°

with the x-axis. Hence, θ=60°

Flux, ϕ=∣E

∣Acosθ =3×10^3×0.01×cos60° =30×1/2

=15Nm^2/C