7. The blue color of the sky results from the scattering of sunlight by air molecules. If the blue light of the sky has a frequency of about 7.5 X 10' Hz, what is the wavelength of this radiation (in m)?

please help with full explanation included! i’m so confused

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.