Step-by-step explanation:
The emf produced in a generator is:
Vemf=25sin(377t)
Recall the standard equation which describes relation between amplitude and angular velocity.
V=asin(ωt)
so substitute the numbers into the equation
Vemf=25sin(377)
to find frequency use the equation
f=w/2π
so freq= 377/2π
this will equal 60Hz