Question

the refractive index of flint glass is 1.65 what is the speed lies in this glass . Given in the speed of light in air is 3×10^8​

Answer 1

Answer:

1.8x10^8 metre/sec

Explanation:

formula is

mu(refrac. index of glass) =speed of light in air÷speed of light in glass flint

1.65=3x10^8÷speed of light in glass flint

or

speed of light in glass flint=3x10^8÷1.65

ie: Answer=1.8x10^8

Answer 2

$\Large \bf Given :$

• $\bf Refractive \: index \: of \: flint \: glass, \: η_{g} = 1.65$
• $\bf Speed \: of \: light \: in \: air, c=3×10⁸m/s$

$\Large \bf To \: Find :$

• $\bf Speed \: of \: light \: in \: glass, v_{g}$

$\Large \bf Solution :$

By formula :

$\bf η_{g} = \dfrac{c}{v_{g}}$

$\bf \implies v_{g} = \dfrac{c}{η_{g}}$

$\bf \implies v_{g} = \dfrac{3 \times 10^{8}m/s}{1.65}$

$\bf \implies v_{g} = \dfrac{3}{1.65}\times 10^{8}m/s$

$\bf \implies v_{g} = \dfrac{3 \times 100}{165}\times 10^{8}m/s$

$\bf \implies v_{g} = \dfrac{\cancel{3} \times 100}{\times{\cancel{165}}_{55}}\times 10^{8}m/s$

$\bf \implies v_{g} = \dfrac{100}{55}\times 10^{8}m/s$

$\bf \implies v_{g} = 1.8181... \times 10^{8}m/s$

$\bf \implies v_{g} = 1.82 \times 10^{8}m/s \: (approx.)$

$\bf \therefore Speed \: of \: light \: in \: glass, v_{g} = 1.82 \times 10^{8}m/s \: (approx.)$