Question

Easy question, what am I doing wrong?
What is the wavelength of light (nm) that has a frequency of 6.44x10^13 s-1 ?
a) 4660
b) 4.66x 10-8
c) 6.49x 10-8
d) 6490
e) 932

Answer 1

and I'm supposed to use c=lambda x v (where c= 3.0x10^8)