1. A rainbow viewed from an airplane may form a complete circle. Where will the shadow of the airplane appear? Explain. 2. A bat flying in a cave emits a sound and receives its echo 0.1 s later. How...

1. A rainbow viewed from an airplane may form a complete circle. Where will the shadow of the airplane appear? Explain.

2. A bat flying in a cave emits a sound and receives its echo 0.1 s later. How far away is the cave wall?

3. Why do radio waves diffract around buildings whereas light waves do not?