$7.$ 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.$)$ e$)$ Find the average power per unit area this wave carries through space. f$)$ Find the average energy density in the radiation. g$)$ What radiation pressure would this wave exert upon a perfectly reflecting surface at normal incidence?