how do you convert this from hertz to do this problem?

Question

i think i know how to do this problem but i dont know how to do the conversion..
calculate the frequency of a photon with a wavelength of 6570 A

i 4got to mention the frequency to be in Hz
i know the formula is c= wavelgnth/ f

Answer 1

The relation between wavelength (L) and frequency (f) is

L = v/f

where v is the wave velocity. For light, that is 3*10^8 m/sec. Convert Angstrom to meters (1 A = 10^-10 m) and use the form

f = v/L

to get f in units of sec^-1 which is hertz,

f = 3*10^8 / 6570*10^-10 Hz

Answer 2

i don't know if this will help..

Equation: f * λ = c

where:
f = frequency in Hertz (Hz = 1/sec)
λ = wavelength in meters (m)
c = the speed of light and is approximately equal to 3*108 m/s