Q. 25

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

Answer :

Assume that the surface is exposed to electromagnetic radiations. So, all the radiations are allowed to fall normally on the given surface.


Let the intensity of the radiation is I and the area of the surface is A.


So, the energy received by the surface in each second is given by,


E = I. A


So, number of photons received by surface in each second is given by,



For the perfectly absorbing surface,


So, force is given by,


Pressure is given by,



Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Source of Electromagnetic waveSource of Electromagnetic waveSource of Electromagnetic wave6 mins
Back to 11th | Interactive Quiz: Waves (part-2)Back to 11th | Interactive Quiz: Waves (part-2)Back to 11th | Interactive Quiz: Waves (part-2)52 mins
Electromagnetic InductionElectromagnetic InductionElectromagnetic Induction50 mins
Back to 11th | Interactive Quiz: Waves (part-1)Back to 11th | Interactive Quiz: Waves (part-1)Back to 11th | Interactive Quiz: Waves (part-1)49 mins
S.H.M.S.H.M.S.H.M.51 mins
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
caricature
view all courses
RELATED QUESTIONS :

Speed of electromagnetic waves is the same

HC Verma - Concepts of Physics Part 2

An electric field and a magnetic field exist in a region. The fields are not perpendicular to each other.

HC Verma - Concepts of Physics Part 2