The magnetic field of a beam emerging from a filter facing a floodlight is given by B0 = 12 × 10-8 sin (1.20 × 107z – 3.60 × 1015 t)T. What is the average intensity of the beam?
Given: The magnetic field of beam is B=12×10−8sin(1.20×107z−3.6×1015t). To find: The average intensity of the beam. The standard equation of the magnetic field of a beam is: B=B0sin(kz−ωt) On comparing the equation of the magnetic field with the standard equation, we have B0=12×10−8 T The intensity of tehe beam is given by: Iav=21μ0B02c⇒21×4π×10−7(12×10−8)2×3×108 ⟹1.71Wm−2
