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Question : 15
Total: 26
(a) Monochromatic light of wavelength 589 nm µ
(b) A double convex lens is made of a glass of refractive index 1.55 , with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is20 cm
(b) A double convex lens is made of a glass of refractive index 1.55 , with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is
Solution:
(a) Calculation of wavelength, frequency and speed
(b) Lens Maker's Formula
Calculation ofR
(a)λ =
= 442.8 nm
Frequencyv =
= 5.09 × 10 12 Hz
Speedv =
m ∕ s = 2.25 × 10 8 m ∕ s
(b)
= [
− 1 ] [
−
]
∴
= [
− 1 ]
∴ R = ( 20 × 1.10 ) cm = 22 cm
(b) Lens Maker's Formula
Calculation of
(a)
Frequency
Speed
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