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heycoa
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Homework Statement
Suppose a laser produces a pulse of light with duration 1 ns, a diameter of 1 cm, and a total energy of 1 mJ. In free space, the pulse length is this 30 cm, the energy density is 42 J/m3, and the irradiance is 1.3*1010 W/m2. Calculate the length, energy density, and irradiance if the pulse with the same duration, diameter, and total energy is instead in a medium with refractive index n = 1.5. Compare the electric fields for the two cases.
Homework Equations
Irradiance = c*ε0/2 * E02
Energy Density = .5*ε0*E2 + .5*B2/μ0
Frequency=c/n
Wave number k=n*ω/c
The Attempt at a Solution
I do not know how "energy density" and "total energy" differ and/or are related. I also am having a difficult time distingushing the separation between free space and a medium with a refractive index. But perhaps my biggest struggle is how to put to use the length, pulse duration, and diameter. I guess this is a geometrical problem however, I just cannot understand how to utilize the measurements.
Please help me understand this. All your help and time is greatly appreciated!
Thank you