An incandescent light bulb radiates uniformly in alldirections with a total average power of 1.0 × 102 W. What is the maximum value of themagnetic field at a distance of 0.50 m from the bulb? (a) 8.4 × 107 T (b) 3.1 × 107 T (c) zero tesla (d) 5.2 × 10–7 T (e) 1.6 × 107 T An incandescent light bulb radiates uniformly in alldirections with a total average power of 1.0 × 102 W. What is the maximum value of themagnetic field at a distance of 0.50 m from the bulb? (a) 8.4 × 107 T (b) 3.1 × 107 T (c) zero tesla (d) 5.2 × 10–7 T (e) 1.6 × 107 T
Explanation / Answer
The intensity of the light is given by I = P/(4r2) Here P = 1.0 × 102 W and r= 0.25m The Maximum value of the electric field is givenby Emax =2 Erms = [2co Erms] Here c =2*108 m/s o=4*10-7 H/m The maximum value of the magnetic field is givenby Bmax = Emax/c substitute the values.