Induction in a loop of wire
Hi there
the problem given is:
A circular loop of wire can be used as a radio antenna. If a 22.0cmdiameter antenna is located 2.20km away from a 95.0MHz source with a total power of 55.0kW, what is the maximum emf induced in the loop? (Assume that the plane of the antenna loop is perpendicular to the direction of the radiation's magnetic field and that the source radiates uniformly in all directions.) As far as I have gotten in solving the problem:
it seems that this problem involves Faraday's law:
EMF= d(phi)/dt
so as loop as perpendicular to propogation, phi is simply B*A.
A=(0.11)^2*3.14 > as per the values given in the problem..
to find B:
we know intensity, I:
55000/(22000^2*4*3.14) = 9.05*10^4 W/m^2
also we know I = EmaxBmax/2(mu_0)
so can find Bmax from this:
=> Bmax = 2.76(10^9)
so (phi) = Bmax*A=1.048(10^10)
so to find d(phi)/dt is it simply a matter of dividing the above value by the frequency that was told in the question (95MHz)?........ or the period maybe???
But this apparantly is not the correct answer.....
Be very grateful if someone could inform me of whatever mistakes I am making...
Andrew
