Across
- 2. to send out a signal by radio waves
- 4. the natural agent that stimulates sight to make things visible
- 5. to use a code to convert symbols into letters
- 7. to convert information into an on off code
- 9. to use a code to convert letters into symbols
Down
- 1. the appearance of objects to the eye with respect to the relative distance and position
- 3. when light shines on a object
- 6. to give off light from a source
- 8. a system of signals or symbols used to