Kepler-186f is an exoplanet that orbits a star other than the Sun. Its star is the red dwarf Kepler-186. It is the first planet to be discovered that orbits its star at a distance like Earth’s distance from the Sun. If Kepler-186f is approximately 5.4 x 1010 meters from Kepler-186, how long does it take for light from the star to reach the exoplanet? The speed of light is 3.0 x 108 m/s. It takes 3 minutes

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.