What is the energy of a photon that emits a light of frequency 6.42 x 1014 Hz? O A. 4.67 x 10-19 J
O B. 3.10 x 10-19 J
O C. 4.25 x 10-19 J
D. 9.69 10-19 J

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.