What speed should a galaxy move with respect to us so that the sodium line at 589.0 nm is observed at 589.6 nm?
1. 164 km/s
2. 332 km/s
3. 102 km/s
4. 306 km/s
Which one of the following is incorrect?
1. | When monochromatic light is incident on a surface separating two media, the reflected and refracted light both have the same frequency as the incident frequency. |
2. | When light travels from a rarer to a denser medium, the speed decreases. The reduction in speed implies a reduction in the energy carried by the light wave. |
3. | In the wave picture of light, the intensity of light is determined by the square of the amplitude of the wave. |
4. | For a given frequency, the intensity of light in the photon picture is determined by the number of photons crossing a unit area per unit time. |