Question

A laser produces an electromagnetic wave with a maximum electric field strength of 1.00×1011 V / m for a time of 1.00 ns. (a) What is the maximum magnetic field strength in the wave? (b) What is the intensity of the beam? (c) What energy does it deliver on a 1.00-mm2 area?

Answer 1

electric field , E = 1 *10¹¹ V/m

time ,t = 1 ns

(a)

maximum magnetic field = electric field/c

maximum magnetic field = 1*10¹¹/(3 *10⁸)

maximum magnetic field = 333.33 T

the maximum magnetic field is 333.33 T.

(b)

Intensity of the beam = 0.5 * E_m²/(c*u0)

Intensity of the beam = 0.5 * (1*10¹¹)²/(3 *10⁸ * 4*pi *10^-7)

Intensity of the beam = 1.32*10²⁰ W/m²

(c)

Energy delivered by the pulse = Intensity * Area * time

Energy delivered by the pulse = 1.32*10²⁰ * 1 *10^-6 * 1 *10^-9

Energy delivered by the pulse = 1.32*10⁵ J