Question

light of wavelength 2000 nm is incident on a glass slab in placed in air refractive index of glass is 1.4 find the speed of incident light in glass​

Answer 1

$\huge\underline\blue{\sf Answer:}$

$\large\red{\boxed{\sf v_{glass}=2.1×{10}^{8}m/s}}$

$\huge\underline\blue{\sf Solution:}$

$\large\underline\pink{\sf Given: }$

• Wavelength ($\lambda$)=2000nm

• Refractive Index ($\mu$)=1.4

• Speed of light in air (c) =$\sf{3×{10}^{8}m/s}$

$\large\underline\pink{\sf To\:Find: }$

• Speed of incident light in glass ($\sf{v_{glass}}$)=?

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We know that ,

$\large{♡}$$\large{\boxed{\sf \mu={\frac{c}{v_{glass}}}}}$

On Putting value :

$\large\implies{\sf 1.4={\frac{3×{10}^{8}}{v_{glass}}}}$

$\large\implies{\sf v_{glass}={\frac{3×{10}^{8}}{1.4}}}$

$\large\implies{\sf v_{glass}=2.1×{10}^{8}m/s}$

$\huge\red{♡}$$\large\red{\boxed{\sf v_{glass}=2.1×{10}^{8}m/s}}$