Geometrical Optics Formulae for NEET

  1. Laws of Reflection of light

    Reflection of light

    • The incident ray, the refracted ray, and normal lie on the same plane
    • Snells law

    sin i/sin r = constant

  2. Relative refractive index

    1n2 = v1/v2

    v1 = velocity of light in first medium

    v2 = velocity of light in second medium

  3. Absolute Refractive index

    n = c/v

    c= velocity of light in air

    v = velocity of light in given medium

  4. Lateral Shift

    Lateral Shift

    Lateral shift

  5. Normal shift on a single surface

    Normal shift Ns= t[1-1/n]

  6. Relation between refractive index and critical angle

    n = 1/sin C

  7. Refraction through a prism

    Refraction through a prism

    Refractive index of the prism n = [sin(A+δ/2)]/sin A/2

  8. Deviation produced by a thin film

    d = (n-1) A

    (n-1) is called the refractivity of the material

  9. Angular dispersion between two colours

    Angular dispersion = (nv-nr)A

    nv, nr is the refractive index of violet light and red light

  10. Dispersive power

    ω = nv– nr/n-1

  11. Lens makers formula for thin lenses

    1/f = (n-1) { 1/R1 – 1/R2}

  12. Power of lens

    P = 1/f

  13. Equivalent focal length of combination of two thin lenses

    1/f = 1/f1 + 1/f2