Studies have shown that congenital amusia is a deficit in fine-grained pitch discrimination and that 4% of the population suffers from this disorder.
Ultraviolet (UV) light is light with higher frequency (lower wavelength) than visible light. UV light has frequencies ranging from 8*1014 to 3*1016 Hz (800 THz to 30 PHz) and wavelengths from 10-8 m to 3.8*10-7 m (10 nm to 380 nm). Prolonged exposure to UV light causes sunburn and can cause skin cancer.
Megahertz means millions of cycles per second, so 91.5 megahertz means that the transmitter at the radio station is oscillating at a frequency of 91,500,000 cycles per second. Your FM (frequency modulated) radio can tune in to that specific frequency and give you clear reception of that station. All FM radio stations transmit in a band of frequencies between 88 megahertz and 108 megahertz. This band of the radio spectrum is used for no other purpose but FM radio broadcasts. In the same way, AM radio is confined to a band from 535 kilohertz to 1,700 kilohertz (kilo meaning thousands, so 535,000 to 1,700,000 cycles per second).