Answer :


Intensity of EM wave = I


Radiation exerts a force on a surface on which it falls, the pressure due to this force is called radiation pressure.

Now, for the surface with area A, then the energy provided is given by,

Now, the total force on the surface is dependent upon the number of photons N

Where, c is the speed of the wave, the wavelength and h is the Planck’s constant.

Now form de Broglie’s theorem for a particle,

where p is the momentum.

The momentum change of a photon when it hits the surface when the surface is totally reflective,

And when the surface is totally absorptive,

Therefore, the force is equal to the change of momentum of all the photons for the totally reflective surface is

And for totally absorptive surface is

And the respective pressures then

A real surface can be partially absorptive and partially reflective; therefore, the pressure will lie between perfectly absorptive and perfectly reflective values. Also real surfaces are more reflective than absorptive, hence

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses

Which mode Physics - Board Papers

Which basic mode Physics - Board Papers

(a) Why arePhysics - Board Papers

Consider the follHC Verma - Concepts of Physics Part 2

An electric fieldHC Verma - Concepts of Physics Part 2

(a) Identify the Physics - Board Papers

How is the speed Physics - Board Papers

An electromagnetiHC Verma - Concepts of Physics Part 2

<span lang="EN-USHC Verma - Concepts of Physics Part 2