A plane electromagnetic wave varies sinusoidally at $82\mathrm{.}2$ as it travels through

vacuum along the positive $.$ The peak value of the electric field is

$2\mathrm{.}08/,$ and it is directed along the positive $.$

a$)$ Find the wavelength.

b$)$ Find the period.

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

d$)$ Write expressions in $$ units for the space and time variations of the electric field. $($ is

in meters, and $$ in seconds.$)$