Question

In a Newtons ring experiment, the radius of the nth bright ring is 0.32 cm and the radius of the (n+19)th dark ring is 0.67 cm. Determine the radius of curvature of the Plano-convex used in the experiment if the wavelength of light used is 589 nm. (4 marks)

Answer 1

Answer:

Explanation:

[June 2005, Set No. 2]

Sol: The given data are

Diameter of Newton’s 15th ring (D15) = 0.59 cm = 0.59×10–2 m

Diameter of Newton’s 5th ring (D5) = 0.336 cm = 0.336 × 10–2 m

Radius of curvature of lens (R) = 100 cm = 1 m

Wave length of light (λ) = ?