Answer:
1341.03 V/m
Explanation:
The power output per unit area is the intensity and also the is the magnitude of the Poynting vector.
= cε₀
⇒ = cε₀
Where;
P is the power output
A is the area of the beam
c is speed of light
ε₀ is permittivity of free space 8.85 × 10⁻¹² F/m
is the average (rms) value of electric field
Making electricfield the subject of the equation
= P / Acε₀
= √(P / Acε₀)
But area A = πr²
= √(P / πr²cε₀)
Given:
Output power, P = 15 mW = 0. 015 W
Diameter, d = 2 mm = 0.002 m
⇒ Radius,
Solving for average (rms) value of electric field;
= 1341.03 V/m
