RBSE Class 12 Physics Notes Chapter 9 Ray Optics and Optical Instruments

These comprehensive RBSE Class 12 Physics Notes Chapter 9 Ray Optics and Optical Instruments will give a brief overview of all the concepts.

Rajasthan Board RBSE Solutions for Class 12 Physics in Hindi Medium & English Medium are part of RBSE Solutions for Class 12. Students can also read RBSE Class 12 Physics Important Questions for exam preparation. Students can also go through RBSE Class 12 Physics Notes to understand and remember the concepts easily. Browsing through wave optics important questions that include all questions presented in the textbook.

RBSE Class 12 Physics Chapter 9 Notes Ray Optics and Optical Instruments

Reflection of Light:
Light is a form of energy which produces in us the sensation of sight and optics is the study of visible light.

Ray Optics:
Ray Optics is that branch of physics which is based on the rectilinear propagation of light.

Laws of reflection:
According tc the laws of reflection :
(i) Angle of incidence is equal to angle of reflection
i.e. i = r

(ii) Incident ray, reflected ray and the normal at the point of incidence all lie in the same plane.
If two plane mirrors are placed at an angle 6 and a point object is held between these two mirrors, then
No. of image formed
n = \(\frac{360^{\circ}}{\theta}\) - 1, if \(\frac{360^{\circ}}{\theta}\) is even integer
and n = \(\frac{360^{\circ}}{\theta}\) , if \(\frac{360^{\circ}}{\theta}\) is an odd integer. 

Spherical mirror:
Spherical mirror is a part of a hollow sphere, whose one side is reflecting and the other is opaque. They are of two types namely concave mirrors and convex mirrors.

RBSE Class 12 Physics Notes Chapter 9 Ray Optics and Optical Instruments

Mirror formula:
For concave mirror and also for convex mirror, the mirror formula is
\(\frac{1}{u}+\frac{1}{v}=\frac{1}{f}\)
where u is object distance, v is image distance and f is the focal length of the mirror.

Assumptions:
Following assumptions are made for driving mirror formula.

  • Aperture of the mirror is small.
  • Incident ray makes small angle with principal axis.
  • Object lies on the principal axis.
  • Object lies on left hand side of the mirror.

Magnification or linear magnification of a spherical mirror is the ratio of the size of the image formed by the mirror to the size of the object.
i.e m = \(\frac{\text { size of image }}{\text { size of object }}=\frac{\mathrm{I}}{\mathrm{O}}\)
Also, m = -\(\frac{v}{u}=\frac{f-v}{f}=\frac{f}{f-u}\)
So, m = \(\frac{\mathrm{I}}{\mathrm{O}}=\frac{v}{-u}=\frac{f-v}{f}=\frac{f}{f-u}\)

Prasanna
Last Updated on Nov. 21, 2023, 9:51 a.m.
Published Nov. 20, 2023