When a wave moves from a dense medium to a less dense medium most of the wave energy is

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87

This is the number of complete movements of a wave per second.

Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 11 cm in diameter, separated by 1.0 cm. how much charge can be added to each of the plates before a spark jumps between the two plates? for such flat electrodes, assume that value of 3×106n/c of the field causes a spark.