A thin sheet of plastic having a refractive index of 1.60 is placed in the path of the interfering beams in an interference experiment using light of 589 nm wavelength. The central fringe shifts through 12 fringes. Calculate the thickness of the sheet in $μ m$ (rounded off to nearest integer).

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Solution

We have, $β = (λ - 1) t = n λ$
Given that $μ = 1.6, n = 12$ and $λ = 589 n m$
$⟹ (1.6 - 1) t = 12 \times 589 \times 10^{- 9}$
$⟹ t = 11.78 μ m$

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A thin sheet of plastic having a refractive index of 1.60 is placed in the path of the interfering beams in an interference experiment using light of 589 nm wavelength. The central fringe shifts through 12 fringes. Calculate the thickness of the sheet in μm(rounded off to nearest integer).

We have, β=(λ−1)t=nλGiven that μ=1.6,n=12 and λ=589nm ⟹(1.6−1)t=12×589×10−9 ⟹t=11.78μm

A thin sheet of plastic having a refractive index of 1.60 is placed in the path of the interfering beams in an interference experiment using light of 589 nm wavelength. The central fringe shifts through 12 fringes. Calculate the thickness of the sheet in $μ m$ (rounded off to nearest integer).

We have, $β = (λ - 1) t = n λ$
Given that $μ = 1.6, n = 12$ and $λ = 589 n m$
$⟹ (1.6 - 1) t = 12 \times 589 \times 10^{- 9}$
$⟹ t = 11.78 μ m$