Concepts Of Physics MCQ Edition [Volume 1]PhysicsDispersion and Spectra
Which of the following quantities associated with a lens depend on the wavelength or wavelengths of the incident light?
Options
- ARadii of curvature
- BFocal length
- CChromatic aberration
- DPower
Correct answer
D. Power
Step-by-step solution
The refractive index of the material of a lens depends on the wavelength of the incident light according to Cauchy's relation = A + B ^2 . The focal length f is given by the Lens Maker's formula 1 f = ( - 1) ( 1 R₁ - 1 R₂ ) . Since depends on , the focal length f depends on the wavelength of the incident light. The power of a lens is P = 1 f , which also depends on because f depends on . Chromatic aberration is the difference in focal lengths for different wavelengths (e.g., f_r - f_v ) due to dispersion. It arises