84. The plano-convex lens (n = 1,5) with the convex side is pressed against the glass plate. A distance between the fourth and third Newton rings observed in reflected light, is 0.4 mm. Determine the optical power of the lens, if the light is produced by monochromatic light with λ = 550 nm falls normally.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)