Question

In Newton's ring experiment we get
the diameter of the 10th ring as 0.5
cm, the wavelength of the light in air
is 6000 Å, how much is the radius of
curvature of the lens. *​

Answer 1

Given info : In Newton's ring experiment we get

the diameter of the 10th ring as 0.5 cm, the wavelength of the light in air is 6000 Å.

To find : the radius of curvature of lens is ...

solution : using formula, $D_n^2=4n\lambda R$

here diameter of nth ring , $D_n$ = 0.5 cm = (5 × 10¯³ m)

nth ring, n = 10

wavelength, λ = 6000 A° = 6 × 10^-7 m

radius of curvature of lens is R

so, (5 × 10¯³)² = 4 × 10 × 6 × 10^-7 × R

⇒25 × 10¯⁶ = 24 × 10¯⁶ × R

⇒R = 25/24 = 1.0417 m

Therefore the radius of curvature of lens is 1.0417 m