Ray Optics and Optical Instruments for JEE

• Use one sign convention throughout (Cartesian is standard)
• TIR happens when light goes from denser to rarer and i > critical angle
• Lens power adds for thin lenses in contact
• Minimum deviation in a prism means the ray passes symmetrically

• Mirror: 1/v + 1/u = 1/f; lens: 1/v − 1/u = 1/f
• Lens maker: 1/f = (μ − 1)(1/R₁ − 1/R₂)
• sin C = 1/μ
• Prism: μ = sin((A + δ_m)/2) / sin(A/2)

Printable Ray Optics and Optical Instruments formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.

• Mixing the mirror and lens formulas
• Sign errors with u and R
• Forgetting that f changes when a lens is placed in water

Appears in almost every JEE Main shift. Very frequent. Solve 30+ PYQs to make the sign convention automatic.

Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.

Question. A compound microscope has an objective made of two thin convex lenses of focal lengths 1 cm and 2 cm placed in contact. The eyepiece has a focal length of 5 cm. The distance between the objective combination and the eyepiece is 20 cm. If the final image is formed at infinity, find (a) the distance of the object from the objective, and (b) the magnifying power of the microscope. Take the least distance of distinct vision as 25 cm.

This example was solved twice independently and both solutions agree.

Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.

• RAY OPTICS in 1 Shot: All Concepts & PYQs Covered || JEE Main & Advanced — JEE Wallah, 8:20:42
  Jump to a subtopic (26)

  • 00:00 Introduction
  • 10:15 Reflection and laws of reflection
  • 25:17 Plane mirror
  • 1:10:16 Spherical mirror
  • 1:17:58 Ray diagrams
  • 1:26:50 Mirror formula and Magnification
  • 1:33:15 Sign convention
  • 1:45:08 Velocity magnification
  • 2:38:09 Refraction and laws of refraction
  • 2:52:57 Glass slab
  • 3:00:00 Total internal reflection
  • 4:09:41 Prism and its types
  • 4:19:49 Deviation of prism
  • 4:24:51 Maximum and minimum deviation
  • 4:34:03 TIR in prism
  • 4:37:40 Thin prism and dispersion
  • 5:06:57 Refraction from spherical surfaces
  • 5:33:36 Shift and apparent depth
  • 5:54:37 Shift by slabs and multiple slabs
  • 6:14:37 Thin lenses and its types
  • 6:40:57 Lens makers formula
  • 7:17:06 Combination of lenses
  • 7:34:01 Important points
  • 7:48:50 Cutting of a lens
  • 7:58:26 Power of concave mirror and convex lens
  • 8:16:57 Thank You Bacchon
• Ray Optics in 1 Shot - All Concepts Covered | JEE Main & Advanced | Class 12 Physics — eSaral - JEE, NEET, Class 9 & 10 Preparation, 2:33:56
  Jump to a subtopic (44)

  • 0:00 Ray Optics
  • 7:25 Mind Map
  • 16:31 Beam of Light
  • 16:53 Laws of Reflection
  • 18:14 Object
  • 19:06 Image
  • 22:08 Properties of Image Formed by a Plane Mirror
  • 23:32 Velocity of Image
  • 26:07 Mirrors at an Angle
  • 28:06 Spherical Mirrors
  • 29:35 Focus and Focal Length of a Mirror
  • 30:07 Focal Length
  • 30:30 Focal Plane
  • 30:58 Ray Tracing Diagram
  • 31:37 Sign−Convention
  • 35:47 Mirror Equation
  • 36:50 Magnification
  • 40:39 Net Magnification
  • 41:24 Graphs
  • 45:17 Newton’s Formula
  • 51:04 Longitudinal Magnification
  • 52:04 Velocity of Image of Moving Object (Spherical mirror)
  • 54:32 Question Practice With PYQ ( Reflection)
  • 1:18:53 Refraction
  • 1:22:13 Laws of Refraction
  • 1:24:14 Atmospheric Refraction
  • 1:25:06 Apparent Depth
  • 1:27:56 Refraction through Parallel Slab
  • 1:28:45 Total Internal Reflection
  • 1:30:17 Angle of Deviation
  • 1:31:30 Prism
  • 1:38:56 Refraction from Curved Surface
  • 1:40:22 Transverse Magnification
  • 1:40:49 Lens
  • 1:42:05 Cutting of Lens
  • 1:44:23 Longitudinal Magnification in Lens
  • 1:45:00 Velocity of Image
  • 1:45:55 Power of Lens
  • 1:46:26 Lenses Kept Very Close to Each Other
  • 1:47:14 Silvering of Lens
  • 1:47:21 Dispersion
  • 1:50:56 Thin Prism
  • 1:52:59 Combination Of Prism
  • 1:58:45 Question Practice With PYQ

• 16 JEE Main 2026 PYQs on Ray Optics and Optical Instruments, with solutions.
• Read the chapter in NCERT textbooks (official, free), then solve its NCERT Exemplar (official, free) questions.
• Chapter-wise past questions: JEE Main and Advanced PYQs and question bank.
• Timed practice tests: NTA Abhyas practice tests (official, free) and our free mock tests.
• See it move: interactive simulation.