complete the crossword puzzle. across 1. one half of the height from the peak of the crest to the lowest point of a wave. 2. unit of wavelenght of electromagnrtic wave. 3. a disturbance in a field that carries energy but does not require a medium to travel. 4. unit of frequency of electromagnetic wave 5. a space where electromagnetic waves can travel 6. lowest part of a wave 7. highest part of a wave 8. electromagnetic waves with lowest frequencies. 9. electromagnetic waves with high energy co distance measured from one crest to the next crest of a wave or from one trough to second trough 11. number of cycles a wave completes in one second