a) Frequency is defined as the no.of vibrations per second.
Wavelength is the minimum distance in which the wave repeats.
Velocity is the speed with which one wave can travel in one second.
Following is the relation between frequency, wavelength, and velocity:
v = fλ
b) Time period = 1/256 s
Velocity of wave = 350 m/s
Frequency = 1 / time period = 256 Hz
We know that,
v = fλ
therefore, wavelength = 1.36 m