Look at Hewitt's "Flash Frequency" question (page 202 in the April 2012, issue ofThe Physics Teacher). In my opinion all three answers, in this multiple choice test are incorrect, in my opinion. My answer would be 0 flashes.
Yes, there are 120 current maxima in each second. But the light intensity, in the case of an incandescent light bulb, is practically constant due to "thermal inertia." Do you agree?