qustions about basi physics....hurry...

All electromagnetic waves (EM waves), including FM waves and red light (visible light) has the same speed in air.

That is 3.0 X 10^8 ms^-1

1. 91.5 MHz = 91.5 X 10^6 Hz = 9.15 X 10^7 Hz

By the equation velocity = frequency X wavelength
3.0 X 10^8 = (9.15 X 10^7) X wavelength
Wavelength = 3.28 m

Therefore, the wavelength of that wave is 3.28 m.

2. 620 nm = 620 X 10^-9 m = 6.20 X 10^-7 m

By the equation velocity = frequency X wavelength
3.0 X 10^8 = Frequency X (6.20 X 10^-7)
Frequency = 4.84 X 10^14 Hz

So, the frequency of the red light is 4.84 X 10^14 Hz.