Ill give 100 points for best answer.

i just need some with the second fact ! i already solved the first one.
my answer for the first fact was: 433.96 seconds but i'm stuck at the second one.

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.