Answer:
1. C speed
2. C Microwaves have a longer wavelength than visible light.
3. D sound
Explanation:
1. An X-ray is an electromagnetic wave. And these are waves that moves with the same speed in air. Thus all X-rays should travel with the same speed in air.
2. For electromagnetic waves, as the wavelength increases across the spectrum; the frequency of the wave decreases. Thus the correct statement is; microwaves have a longer wavelength than visible light.
3. Since electromagnetic waves moves with the same velocity (i.e the speed of light), then sound waves would not reach the earth. The correct option is D.
