Respuesta :
The total energy transported per hour along a narrow cylindrical laser beam 2. 40 mm in diameter, whose b-field has a RMS strength of 1. 30×10−10 will be 6.40 × 10⁻⁸J.
Intensity for an electromagnetic wave is energy crossed per second in the direction perpendicular to the propogation of electromagnetic wave which is passing per unit area.
The Intensity for an electromagnetic wave is given by:
I = cε₀E₀²
where c is the speed of light,
E₀ is the maximum value of the electric vector
ε₀ is the permitivitty of medium
I is the intensity
We know that, E = Bc
where, B is the magnetic field
Hence on substituting into the formula:
I= cε₀E₀²
⇒ I= c³ε₀B²
Given,
B = 1.30×10⁻¹⁰ T
So,
I = (3 X 10⁸)³ X (8.85 X 10⁻¹²) x(1.10×10⁻¹⁰)²
⇒ I = 96.37 × 10⁻⁸ W/m²
Energy transported per unit hour is :
E= AIt
where A is the area of beam = πr²
r is the radius of beam used, r = 1.20mm = 0.0012m
t is the time = 1hr = 3600s
On substituting,
E = 2.891 × 10⁻⁶ × πr² × 3600
E = 2.891 X 10⁻⁶ × 3.14 × (0.0012)² x (3600)
E = 6.40 × 10⁻⁸J
Hence, total energy transported per hour along a narrow cylindrical laser beam is 6.40 × 10⁻⁸J.
Learn more about electromagnetic waves here, brainly.com/question/13803241
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