Consider the electric generator with the general specification first in (a-c), i
ID: 1503447 • Letter: C
Question
Consider the electric generator with the general specification first in (a-c), in (d) evaluate: N turns coil with diameter d, rotating with frequency f in magnetic field B What is magnetic flux? How does here the magnetic flux through the coil change with time, when the coil is rotating with constant f (angle is steadily increasing with time, how?)? phi=. Assume that at t=0 the coil is orientated perpendicular to B (at angle=0) that the flux has its maximum value, (keep symbols, do not evaluate) Find the change of flux in time (d phi/dt) and use Faraday's law to get the induced emf or voltage V(t)=.. (at this coil (with N,d) rotating with frequency f in a field B); sketch the function V vs t. Label the peak value and the period. Now evaluate B with the given values: A 5-turn coil 1.0 cm in diameter is rotated at 10 rev/s about an axis perpendicular to a uniform magnetic field. A voltmeter connected to the coil through rotating contacts reads a peak value 360 mu V. What's the magnetic-field strength?Explanation / Answer
a) flux = BAcos(phi)
b) d(phi)/dt = BAwsin(phi)
c) V = ndphi/dt = NBAwsin(wt)
d) V vs T is the sin curve
e) N = 5
w = 10*2*pi = 62.8 rad/s
Vmax = 360*10^-6 V = 5*B*pi*(0.5*10^-2)^2*62.8
B = 0.0146 T