Calculate the frequency of the light emitted when an electron in a hydrogen atom makes each transitions.?

Question

n=4 => n=3 ? v = ________________ s^-1
n=5 => n=1 ?
n=5 => n=4 ?
n=6 => n=5 ?

I got the first one correct (1.6*10^14) but the rest i am getting wrong. Can anyone help me solve the last 3 questions?

Answer 1

#2
1/wavelength = R(1/1^2 - 1/5^2)
Then c = f*w and solve for f.

Answer 2

You were probably doing it right. Frequencies just can’t be negative. So don’t add the negative sign.