Q1. Antennas for radio transmission and reception are particularly effective if they're about a half-wavelength long. What's the appropriate length for an FM antenna, taking 90MHz as a typical FM frequency? (You may have used such an antenna with your FM receiver.) Express your answer to two significant figures and include the appropriate units.
Q2. Light travels at about 0.75c in water. What's the wavelength in water of light whose wavelength in vacuum is 642nm ? Express your answer to two significant figures and include the appropriate units.