Answer:
140 Hz
Explanation:
Frequency is the reciprocal of period hence f=1/T
Here, the frequency is 140 times per second hence the period will be 1/140= 0.0071428571428 s
Rounded off to 3 significant figures then the period is 0.00714 s or 0.714 ms
Otherwise, the frequency is already given as 140 cycles per second which is equivalent to 140 Hz