JEE Main Physics · Ray Optics PYQ
JEE Main Ray Optics Previous Year Questions (2002–2025)
Ray Optics is a P1 high-ROI Physics chapter — ~5% JEE Main weightage with 1–2 questions per session. Combined with Wave Optics (~3%), Optics contributes ~8% — dense yield for relatively short preparation time. Mirror/lens formula, refraction through prism and optical instruments are the recurring question templates.
Ray Optics PYQs from 2002 to 2025, tagged by sub-topic (reflection, refraction, lens formula, prism, optical instruments). Every solution includes ray diagrams where relevant.
Ray Optics at a Glance
Key Sub-Topics & What's Tested
Reflection at Plane & Curved Surfaces
Laws of reflection, image formation by plane mirrors, concave and convex mirrors, mirror formula (1/v + 1/u = 1/f), magnification.
Refraction at Plane Surfaces
Snell's law (n₁ sin θ₁ = n₂ sin θ₂), refractive index, total internal reflection (TIR), critical angle.
Refraction at Spherical Surfaces & Lenses
Lens maker's formula (1/f = (n-1)(1/R₁ - 1/R₂)), thin lens formula (1/v - 1/u = 1/f), combination of lenses (1/f_eq = 1/f₁ + 1/f₂).
Prism
Deviation through prism (δ = (n-1)A for small angles), minimum deviation, dispersion (separation of colours in white light).
Total Internal Reflection
Condition (light going from denser to rarer, angle > critical angle), applications (optical fibres, sparkling of diamond, mirage).
Optical Instruments
Simple microscope, compound microscope (magnification M = M_objective × M_eyepiece), astronomical telescope.
Human Eye & Defects
Eye structure, near point, far point, myopia (correction with concave lens), hypermetropia (convex), astigmatism, presbyopia.
Scattering & Colour
Rayleigh scattering (∝ 1/λ⁴), why sky is blue and sunset is red, dispersion in rainbows.
Question Type Distribution
| Question Type | Share (approx) | Example Pattern |
|---|---|---|
| Mirror/Lens Formula Application | 25% | Find image distance when object is 15cm in front of concave mirror with focal length 10cm. |
| Refraction / Snell's Law | 20% | Light travels from water (n=1.33) to glass (n=1.5) at 30° — find refraction angle. |
| Lens Combination | 15% | Two thin lenses of focal lengths +20cm and -30cm in contact — find equivalent focal length. |
| Prism Problem | 15% | Find minimum deviation for a prism of angle 60° and refractive index 1.5. |
| Optical Instruments | 15% | Find magnifying power of compound microscope with objective f=1cm and eyepiece f=5cm. |
| TIR / Critical Angle | 10% | Critical angle for water-air interface (n_water = 1.33) is — ? |
How to Solve Ray Optics PYQs
- 1Use sign convention consistently. Distances measured from pole: positive if in direction of incident light, negative otherwise. Focal length is positive for convex lens, negative for concave.
- 2Mirror/lens formula template. 1/v + 1/u = 1/f for mirrors. 1/v - 1/u = 1/f for lenses. Magnification m = -v/u for mirrors, v/u for lenses.
- 3For combination of lenses, work in terms of power. P = 1/f (diopters). P_eq = P₁ + P₂ + ... for thin lenses in contact. Easier than working in focal lengths.
- 4Prism at minimum deviation. Light passes symmetrically through prism (i₁ = i₂). Use formula (A + δ_m)/2 = sin⁻¹(n × sin(A/2)). Classic template.
- 5Optical instruments: know the standard formulas. Compound microscope: M = (L/f_o) × (D/f_e). Telescope (normal adjustment): M = f_o/f_e. Memorise and apply directly.
Common Mistakes That Cost Marks
- Wrong sign convention in mirror formula. Distances on the same side as incoming light are negative. Forgetting this inverts the answer.
- Using Snell's law with wrong index ordering. n₁ sin θ₁ = n₂ sin θ₂, where n₁ is the medium light is coming FROM, not the incidence plane. Careful with ordering.
- Confusing lens power and focal length. Power P = 1/f where f is in metres (not cm). Using cm gives wrong diopter values.
- Missing TIR condition. Total internal reflection requires light going from denser TO rarer medium. Going the other way can never TIR, regardless of angle.
- Treating thin lens like thick lens. Lens maker's formula 1/f = (n-1)(1/R₁ - 1/R₂) is for thin lens. Thick lens requires additional terms rarely tested in JEE Main.
Related JEE Main Practice
Frequently asked questions
How many Ray Optics PYQs should I solve?
Target 60–80 PYQs across 2010–2025. Given ~5% weightage and short chapter, focused practice quickly reaches very high accuracy.
Is Ray Optics or Wave Optics more tested?
Ray Optics (5%) is slightly more tested than Wave Optics (3%). Both use different frameworks — master Ray Optics first, then Wave Optics.
Do I need to memorise all optical instrument formulas?
Yes for common ones: compound microscope, astronomical telescope (normal adjustment). Simple microscope formula too. ~5 formulas total that appear repeatedly in PYQs.
What's the most-tested Ray Optics PYQ template?
Object distance vs image distance in mirror/lens formula. Appears in 3–4 PYQs per 10-year window. Master the sign convention.
How detailed should my knowledge of eye defects be?
NCERT-level: know myopia (corrected by concave lens), hypermetropia (convex), astigmatism (cylindrical lens), presbyopia (bifocal). Lens power calculations for corrections come up occasionally.
Does Ray Optics connect to Wave Optics PYQs?
Rarely overlap in PYQs — they're typically separate questions. Ray uses geometrical principles; Wave uses interference/diffraction. Study them independently.
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