Hello, can someone please check my answers and tell me if they are correct?

Question

1. A laser produces a pulse of light with a speed of 300000000m/s in vacuum in a time 1.70x10^-15s.
a) what is the length of the pulse?
b) The pulse travels into a piece of glass in which it's lenghth is 3.75x10^-7m. What is the speed of light in the glass.
My answers were 5.10x10^-7m and 2.21x10^8 m/s respectively.

2. You flick a rope, sending a pulse down it toward your friend. If the pulse takes 1.81s to travel the length of the 10 m rope, and has a length of 1.16m, how long did it take you to produce it?
My answer was 2.10x10^-1s.

3. Most radio stations use antennas which are a quarter of the length of the wavelength they produce.
a)One FM radio station has a frequency of 88.5 MHz. Radio, like all forms of electromagnetic radiation, travels at a speed of about 3.00x10^8 m/s in air. How long should the antenna for this FM radio station be?
b) A typical AM radio station has a frequency of 530 kHz. How long should the antenna be for this radio station?
My answers were 8.47x10^-1m and 1.42x10^2m respectively.

4. The musical note G6 has a frequency of 1568 Hz. If the speed of sound in an auditorium is 347m/s, what is the wavelength of G6 in the auditorium.
My answer was 0.221m.

Thanks!

Answer 1

3a. L = V/F = 3*10*8/8.85*10^7 = 3.39 m = Wavelength.

La = 1/4 * 3.39 = 0.85 m. = Length of antenna.

b. L = V/F = 3*10^8/5.3*10^5 = Wavelength.

1/4 * wavelength = Length of antenna.

4. L = V/F = 347/1566 = 0.222 M.