1. On a spacecraft sent to Mars to take pictures, the camera is triggered by radio waves, which like all electromagnetic waves travel with the speed of light. What is the time delay between sending the signal from the earth and receiving it on Mars? (Take the distance to Mars to be 9.7 × 10¹⁰ m.)

2. A circularly polarized wave is said to be right circularly polarized if the electric and magnetic fields rotate clockwise when viewed along the direction of propagation and left circularly polarized if the fields rotate counterclockwise. What is the sense of the circular polarization for the wave described by the expression in Problem 57? What would be the corresponding expression for a circularly polarized wave of the opposite sense?