Electromagnetic Waves

An expression for oscillating electric field in a plane electromagnetic wave is given as E_z = 300 sin(5$\pi$ $\times$ 10³x $-$ 3$\pi$ $\times$ 10¹¹t) Vm^$-$1 Then, the value of magnetic field amplitude will be : (Given : speed of light in Vacuum c = 3 $\times$ 10⁸ ms^$-$1)