Problem 1 Prove the vector identities V.E= jk E and VXE = jkxE for plane monochromatic waves

The ship in the figure below travels along a straight line parallel to the shore and a distance d = 700 m from it. The ship's radio receives simultaneous signals of the same frequency from antennas A and B, separated by a distance L = 810 m. The signals interfere constructively at point C, which is equidistant from A and B. The signal goes through the first minimum at point D, which is directly outward from the shore from point B. Determine the wavelength of the radio waves.

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2 Problem 2 Assume two adjacent interstellar gas clouds with known thickness dị and d2 found in front of an astronomical light source. Suppose that this source emits a beam of radiation with known specific intensity 1, as it enters the first cloud of interstellar gas. Calculate the specific intensity I, immediately after this beam has traversed the two clouds of gas. Assume that the densities (p1 and p2) and the opacities (k,1 and ky,2) are constant within the clouds and are known quantities and that these clouds possess no emissivity. (Note the relationship between the opacity and absorption coefficient a, = pk,. See Rybicki and Lightman eq. 1.22.) %3D

What is the difference between a continuous spectrum and a discrete spectrum? O A discrete spectrum is represented by distinct spectral components. A continuous spectrum represents a sound that continues indefinitely. O A discrete spectrum represents a sound that is turned on and off. A discrete spectrum is represented by an area under a curve.