Question

At one instant, the electric and magnetic fields at one point of an electromagnetic wave are E = (200i + 310 j – 50k)V/m and B = (7.2î – 7.0j + ak)Bo.

Answer 1

Ans! The are given electric and magnetic fields - E = (200 ê + 3109-50%) V/m B = (7.2 î - 7.0 h +9²) Bo a) As we know electric field perpendicular E B that in electromagnetic wave and magnetic field are always so, & B caso = E. Blasgo=0 Now put value of È and B we get, (200 [ +3 109-50?). (7:22-7h + a2) Bo = 0 (1440-2110-50a) Bo =0 -730-50a =o so a a = -730 = -14.6 a = -14.6 . [a=-1406 Hence, B=(7.21-79 + 8+1 4.6) f) Bo b) we know that Ielc ie ratio of electric and magnetic field in e.m wave is equal to velocity. So, TE1 = √(200) 2 + (310) + (-5032 = Magoo + 96100 + 2500 = √ 138,600 = 372.29

B = |(11.2)+(-2)2 + (-141632]Bo- - Bor 314 - 17-72 Bo 372.29 – 3x108 17.72 Bo Then, Bo= 372.29 3X10 PX 17:72 - 372.29 410-8 53.16 Bo= 7x108 - 0.07 UT Bo= 0.07 UT (6) As we know that poynting vector: P- ICEXB) for n-component ! PHLEX B) Then, u = 1.26 X10-b Tm At Then, P = (2000+ 3109-502 X (72225-1962 w 0.07 T X10x10 200 310 -so 7.2 -7 -14.6 1.26810-6 0.07

Now, Then, I 7 } | 200 310-50 - 4116 ê +2560 h - 3632 1. 1 7.2 7 -14.67 P = 0.05{(41761) +(2560 jpt 36341)] = 208.80 ê + 128 ↑ +-181.60) Î ... (1) poynting vector is P = (208.80 [ + 128 9-181-607) was Hence, Now, x-component of poynting vector P = 208.80 m2 d) from equ W - component of poynting vectors - 128 wm2 (e) from eqh U 2 component of poynting vector P = -181.600 m2