An electromagnetic wave has an electric field given by the expression (in Cartesian co-ordinates) : →E(x,t)=6.0cos(1.4×107x−3.43×1015t)^z. What is the direction of the magnetic field at time t = 0 and position x = 0 ?
The correct option is D -y ∵→E×→B||→V where →V represents the direction of propogation. Given that wave is propagating along + x-axis and →E along z-axis. Hence →E×→B=+^i ⇒^k×→B=+^i⇒→B is along−^j