Question

Part 1: A plane electromagnetic wave propagates in vacuum. Its electric field is given by the mathematical expression Ex = 235 cos 0.63m?1 z ? 1.9 × 108 s ?1 t V/ (for refrence).

Actual Question :

According to the above expression, at a particular instance in time, the electric field is along the +x direction. Indicate the magnitude and direction of the wave’s magnetic field at the same instance. (Hint: The right-hand rule applies.) A. 78 × 10?8T, z direction B. 235 × 10?8T, z direction C. 78 × 10?8T, y direction D. 78 × 10?8T, ?y direction E. 235 × 10?8T, y direction

Answer 1

B_0 = E_0/C = 235/ 3 times 10^8 = 78.33 times 10^-8 T TildeEqual 78 times 10^-8 T E_X = 235 cos[(0.632) - 91.9 times 10^8 t)] along leftarrow this shoes that prapagates in +z direction as it followes the general expression coa(kz - wt) everther direction of prapagation is along E^up arrow_downarrow along i times B^rightarrow _downarrow let it be along a unit vector B I times B = k the know i times j = k so B^rightarrow is along j i,e +y - direction correct answer: C