Light can be seen as an electromagnetic wave.
What happens when two waves, with the same frequency, superpose is called interference.
If at a certain point two waves arrive both with a crest, we have constructive interference and the amplitudes sum up, reaching the maximum value, resulting in bright spots.
If at a certain point one of the waves arrives with a crest and the other wave arrives with a trough, we have destructive interference, and the two amplitudes cancel out, resulting in dark spots.
Therefore, t<span>he dark bands on the wall are from destructive interference.</span>
Answer:
helium, neon, argon,krypton, xenon, and radonoccupying Group 0 (18) of the periodic table. They were long believed to be totally unreactive but compounds of xenon, krypton, and radon are now known.
The Sun is a star around which our planet Earth and other planets and satellites of our solar system revolve along specific orbits. Sun appears to be spherical in shape and consists of glowing hot gases. It contains mostly hydrogen and helium gases. The temperature of the gas mixture is extremely high.
Therefore, the Sun mostly composed of hydrogen and helium gases.
(Answer) B. Composition mostly hydrogen and helium gas, Mass 1.989 x 10^30 Kg
