The magnetic field of a beam emerging from filter facing a floodlight given by B0 = 12 × 10-8 sin (1.20 × 107 z - 3.60 × 1015 t)T.
What is the average intensity of the beam?
Hint: The average intensity of the beam depends on the magnitude of the magnetic field.
Step 1: Find the magnitude of the magnetic field.
Magnetic field, B=B0sinωt
Given, equation B = 12×10-8 sin1.20×107z-3.60×1015t T
On comparing this equation with the standard equation, we get;
B0=12×10-8 T
Step 2: Use the formula of average intensity.
The average intensity of the beam;
Iav=12B02μ0.c=12×12×10-82×3×1084π×10-7
=1.71 W/m2