Problems on light as radiation
Problem 2.1:
Compute the energy density of a 2.0 mW laser beam with a diameter of 2mm.
[Solution]
Problem 2.2:
The power per unit area incident on the earth due to sunlight is about
1.4 kW/m
2. What is the
approximate magnitude of the electric field vector on sunlight near the earth (
μ0≡4π×10-7 N.s
2/C
2)?
[Solution]
Problem 2.3:
Write an expression (in SI units) for the magnetic field of a 10 MHz light wave traveling in the negative
z
direction and an electric field amplitude of
.
[Solution]
Problem 2.4:
Consider the following electric and magnetic waves:
Show that these waves satisfy Maxwell's equations in free space. What conditions must be satisfied?
[Solution]
Problem 2.5:
Consider a 60W light bulb. Assume that all radiation given off is in the form of light of
wavelength 650 nm. Calculate the number of photons given off per second.
[Solution]
.
[Solution]
