1. 2 way radio
2. radio waves
3. communication
4. convert the voltage from a transmitter into a radio signal
5. signal strength refers to the transmitter power output
6. sorry, not so sure.. Though it might be the waves.
It's the angle made by the incident ray when it's perpendicular to the surface. (Perpendicular lines are the lines that form a graph or like a 90-degree angle)