The voltage of an electromagnetic wave traveling on a

The voltage of an electromagnetic wave traveling on a transmission line is given by v (z, t) =5e-az sin (4p x 109t – 20p2) (V), where z is the distance in meters from the generator.
(a) Find the frequency, wavelength, and phase velocity of the wave.
(b) At z = 2 m, the amplitude of the wave was measured to be 1 V. Find a.