Show that the radiation pressure exerted by an EM wave of intensity I on a surface kept in vacuum is `I//c`.

Explanation

Pressure `=("Force")/("Area") =(F)/(A)`
Force is the rate of change of momentum
`"i.e., "" "F=(dp)/(dt)`
`"Energy in time dt"" " U=p.C " or " p =U/c`
`:. " ""Pressure" = 1/A .(U)/(C.dt)`
`" prssure" =I/C " "[":." I = "Intensity" =(u)/(A.dt)]`