Ray Optics and Optical Instruments: One-Page Formula Sheet

Ray Optics and Optical Instruments — formula sheet

Formulas

• 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)

Key ideas

• 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

Traps to avoid

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

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