Suppose an intelligent society capable of receiving and transmitting radio signals lives on a planet orbiting zagnut, a star 116 light-years away from earth. if a signal were sent toward zagnut in 1999, what is the earliest year that earth could expect to receive a return message? (hint: a light-year is the distance a ray of light travels in one year.)

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.