A convex lens of crown glass is perfectly cemented to a plano-concave lens of flint glass to form an achromatic combination of power `div 5D`. Calculate the radii of curvature of the convex lens from the following data.
`{:(,"Refractive index",,"Dispersive power"),("Crown glass"," "1.50,," "0.1),("Flint glass"," "1.60,," "0.02):}`
