The e.m.f. of a.c. Generator is given by `E = 200 sin (100 pi t+ pi//3)`
where E is in volt and t in sec.
Which is the correct option from the following?

Options

A. The peak value of the e.m.f. is `200sqrt(2)V`
B. At time t=0, the plane of the coil is perpendicular to the field
C. At times t=0, the plane of the armature makes an angle of `60^(@)` with the magnetic field
D. The frequency of rotation of the armature is 50 Hz

Answer

D

Explanation

a,b and c are wrong because (i) the peak value of the e.m.f. = 200V (ii) at time `t=0, E=E_(0) sin (pi//3)` or `alpha = (pi)/(3)` i.e. the plane of the armature makes an angle of 60^(@) with the magnetic field. The angles are not measured with the plane of the coil. However angular frequency `omega t = 100 pi t`
`:. 2 pi n =100 pi :. n = 50 Hz`
`:.` (d) is the correct option.