Ray Optics One-Shot Revision Notes
Ray Optics One-Shot Revision Notes
Class 12 Physics | Board Exams | NEET | JEE
Agar aap Class 12 Physics ke chapter Ray Optics and Optical Instruments ko exam se pehle jaldi revise karna chahte hain, to ye One-Shot Revision Notes aapke liye perfect hain. Yahan sabhi important formulas, concepts aur keywords ko simple Hinglish me explain kiya gaya hai.
1. Reflection & Refraction Basics
- Law of Reflection: Angle of Incidence (i) = Angle of Reflection (r).
- Incident Ray, Normal aur Reflected Ray ek hi plane me hote hain.
- Snell's Law:
sin i / sin r = n2 / n1 = 1μ2 - Refraction me Speed aur Wavelength change hoti hai lekin Frequency same rehti hai.
- Refractive Index:
n = c / v
2. Spherical Mirrors & Lens Formula
Important Formulas
- Mirror Formula : 1/f = 1/v + 1/u
- Lens Formula : 1/f = 1/v − 1/u
- Magnification (Mirror) : m = −v/u
- Magnification (Lens) : m = v/u
New Cartesian Sign Convention:
Light ki direction me distance Positive (+) aur opposite direction me
Negative (-) liya jata hai. Pole (P) ko Origin maana jata hai.
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3. Total Internal Reflection (TIR) & Prism
-
Conditions of TIR
- Light Dense Medium se Rarer Medium me jaye.
- Angle of Incidence Critical Angle se bada ho.
-
Critical Angle Formula:
sin C = 1 / n -
Prism Formula:
n = sin[(A + δm)/2] / sin(A/2)
4. Optical Instruments
Board Exam aur NEET/JEE me Optical Instruments ke formulas frequently pooche jaate hain.
| Instrument | Magnifying Power |
|---|---|
| Simple Microscope | m = 1 + D/f |
| Compound Microscope | m = -(L/fo) × (1 + D/fe) |
| Astronomical Telescope | m = -fo/fe |
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5. Exam Tips
- Mirror aur Lens Formula hamesha yaad rakho.
- Sign Convention me sabse zyada mistakes hoti hain.
- TIR aur Critical Angle numericals practice karo.
- Prism Minimum Deviation Formula important hai.
- Microscope aur Telescope ke formulas directly pooche jaate hain.
Quick Revision
| Reflection | i = r |
| Snell's Law | sin i / sin r = n₂ / n₁ |
| Refractive Index | n = c/v |
| Mirror Formula | 1/f = 1/v + 1/u |
| Lens Formula | 1/f = 1/v − 1/u |
| Critical Angle | sin C = 1/n |
| Telescope | m = -fo/fe |