1. A spherical lightbulb with a diameter of 3.20cm radiates light equally in
all directions, with a power of 4.50 W.
(a) Find the flux at the surface of the bulb.
(b) Find the flux 7.20 m from the center of the bulb.
(Here the light bulb may be treated as a point source.)
(c) At this 7.20 m distance, a lens is set up with its optical axis
aligned with the bulb. The lens has a circular cross-section with a diameter
of 15.0 cm and a focal length of 35.0 cm. Find the diameter of the image of
the bulb.
(d) Find the flux of the image.
2. In this problem, you will sketch the wave described by E = 10 sin(kx - wt + ε), where ε = initial phase of the wave. Take t = 0 and make a plot of the two waves corresponding to ε = 0 and ε = π/2. Take various values of x to make the plot (x = 0, λ/4, λ/2, 3λ/4, λ). What does the phase-shifted wave look like?
3. 24.P.40
Last updated September 26, 2009