A plane electromagnetic wave varies sinusoidally at $96\mathrm{.}6$ MHz as it travels through vacuum along the positive x direction. The peak value of the electric field is $2\mathrm{.}16$ mV$/$m$,$ and it is directed along the positive y direction.

$($a$)$ Find the wavelength.

m

$($b$)$ Find the period.

ns

$($c$)$ Find the maximum value of the magnetic field.

pT

$($d$)$ Write expressions in SI units for the space and time variations of the electric field. $($x is in meters, and t in seconds.$)$

magnitude$$ E $=()$ cos $2($ x $$ t$)$ direction