Power for Single Sample T-Test - need someone to check solution

#1
Power for Single Sample T-Test?

I need someone to verify if i've calculated power correctly for this question.

A well known test has a M = 520 and SD = 80. A researcher thinks that a certain alteration in the test content can raise the Mean score from 520 to 550.

a) What is the effect size
b) What is the value of delta (non-centrality parameter) if n = 100?
c) what is the power of the test?

a ) effect size = M1 - M2 / SD
= 550 - 520 / 80
= 0.375
b) delta = effect size * sqrt (n)
= 0.375 * sqrt (100)
= 3.75

c) with Delta = 3.75, alpha level = 0.05 (assuming two tails)

Power = .38
(I consulted a table of Power as a function of alpha)

Can anyone confirm my solution?