Ray Optics and Optical Instruments Important Questions for NEET 2025: Ray Optics and Optical Instruments chapter contributes around 4%–5% of Physics questions in NEET. Typical questions involve mirror/lens formulae, TIR, refraction, power of lenses, and applications in microscopes and telescopes.
Most Expected NEET Questions (with Solutions)
| Question | Concept | Answer (Brief) |
|---|---|---|
| 1. State mirror formula and its sign convention. | Concave/convex mirror | \( \frac{1}{f}=\frac{1}{v}+\frac{1}{u} \); distances measured from pole. |
| 2. Derive critical angle for TIR. | Total internal reflection | \( \sin i_c = \frac{n_2}{n_1} \) where \( n_1>n_2 \). |
| 3. What is the focal length of a double convex lens with R₁=20cm, R₂=30cm, n=1.5? | Lens Maker’s Formula | \( \frac{1}{f}=(n-1)(\frac{1}{R_1}-\frac{1}{R_2}) \Rightarrow f=12cm \). |
Quick Quiz (2 Questions) + Answers
Answer: In TIR, reflection occurs within the denser medium when \( i>i_c \); in reflection, light bounces off a surface interface.
Answer: \( m = 1 + \frac{D}{f} \), where D = least distance of distinct vision (25 cm).
FAQs
Usually 2–3 questions, totaling ~8–12 marks.
Mirror & lens formulae, Snell’s law, TIR condition, and lens maker’s equation.