Question

3. The polarizing (or Brewster) angle is defined as the angle of incidence at a boundary between two media, for which the reflected and the refracted rays are perpendicular to each other. If the polarizing angle for light traveling in air reflecting off a certain type of glass is 53°, what is the speed of light in the glass? a) 1.80×108 m/s b) 1.60×108 m/s c) 2.26×108 m/s d) 2.52×108 m/s e) 2.02×108 m/s

Answer 1

Answer:

Speed of light in the glass $v=2.26\times 10^8 ms^{-1}$

Explanation:

In this question we have given

angle of polaization,p=$53^o$

we have to find the speed of light in the glass,v=?

We know that, refractive index of glass can be determined by following formula

$n=\frac{c}{v}$................(1)

here,

c- speed of light in air

v-speed of light in glass

we also know according to brewester's law refrective index of glass is given as

n=tanp......................(2)

here p-angle of polarization

From equation (1) and equation (2)

we got

$\frac{c}{v}=tanp$

put value of c=$3\times 10^8 ms^{-1}$ and p=$53^o$ in equation 3

we got

$\frac{3\times 10^8 ms^{-1}}{v}=tan53$

$v=\frac{3\times 10^8 ms^{-1}}{tan53}\\v=\frac{3\times 10^8 ms^{-1}}{1.32}\\v=2.26\times 10^8 ms^{-1}$