An achromatic doublet is constructed by combining two thin lenses in contact of focal lengths $f_{1}$ and $f_{2}$ made of glasses with dispersive powers $ω_{1}$ and $ω_{2}$ . What is the condition for achromatism?

Practise more Ray optics and optical instruments.

Free questions with an explanation for every one, and full timed JEE Main mock tests.

All Ray optics and optical instruments questions Take a mock test

More Ray optics and optical instruments questions

An object is placed at a distance of $30 cm$ in front of a concave spherical mirror of focal length $f = 20 cm$ . What is the…
A biconvex thin lens made of glass with refractive index $n = 1.50$ has radii of curvature $R_{1} = 20 cm$ and $R_{2} = - 30 cm$ .…
What is the critical angle $θ_{c}$ for total internal reflection at a glass-water interface, if the refractive index of glass is…
Two thin convex lenses of focal lengths $f_{1} = 20 cm$ and $f_{2} = 30 cm$ are placed in coaxial contact. What is the optical p…
A prism of refracting angle $A = 6 0^{\circ}$ produces a minimum angle of deviation $δ_{m} = 3 0^{\circ}$ . What is the refractive index of the…
An astronomical telescope in normal adjustment has an objective lens of focal length $f_{o} = 100 cm$ and an eyepiece of focal length…