Home
Class 12
PHYSICS
If 2 .5 xx 10^(-6) N average force is ex...

If `2 .5 xx 10^(-6) N` average force is exerted by a light wave on a non-reflecting surface of `30 cm^(2)` area during 40 minutes of time span, the energy flux of light just before it falls on the surface is `"____________" W //cm^(2)`. ( Round off to the Nearest Integer )
(Assume complete absorption and normal incidence conditions are there )

Text Solution

Verified by Experts

The correct Answer is:
25
`F = (IA)/( c)`
`F = (P)/(c)`
`2 . 5 xx 10 ^(-6) = (P)/( 3 xx 10^(8))`
`7 . 5 xx 10 ^(2) = P`
Energy flux ` = (P)/(A) = (7 . 5 xx 10^(2))/(30) = 25 W//m^(2)`
Energy flux = 25 `W//m^(2)`
Promotional Banner

Similar Questions

Explore conceptually related problems

Light with energy flux of 18W//cm^(2) falls on a non reflecting surface of area 20cm^(2) at normal incidence the momentum delivered in 30 minutes is

Find energy absorbed by the surface of area 30 cm^2 in 40 minutes. If force applied by light is 2.5 xx10^-3 N normally?

Light is falling on a surface of area 3m^2 normal to it . Energy flux of light is 10^6 W/m ""^2 . .find the avaerage force exerted on the surface in a time interval of 100 seconds assume that surface is completely reflecting .

Light with an average flux of 20 W/cm^2 falls on a non-reflecting surface at normal incidence having surface area 20 cm^2 . The energy received by the surface during time span of 1 minute is:

Light with an energy flux of 18W//cm^(2) falls on a non-reflecting surface at normal incidence. The pressure exerted on the surface is

Light with an energy flux 20 W//cm^2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm^2 . the total momentum delivered ( for complete absorption)during 30 minutes is

Light with an energy flux of 40W//cm^(2) falls on a non-reflecting surface at normal incidence. If the surface has an area of 20cm^(2) , find the average force exerted on the surface during a 30min time span.