Use the exact values you enter to make later calculations. A ray of light strike

Question

Use the exact values you enter to make later calculations.

A ray of light strikes a flat, 2.00-cm-thick block of glass (n = 1.99) at an angle of = 34.2° with respect to the normal (see figure below).

(a) Find the angle of refraction at the top surface and the angle of incidence at the bottom surface.
_______°

(b) Find the refracted angle at the bottom surface.
________°

(c) Find the lateral distance d by which the light beam is shifted.
________cm

(d) Calculate the speed of light in the glass.
_________m/s

(e) Calculate the time required for the light to pass through the glass block.
________s

(f) Is the travel time through the block affected by the angle of incidence?

-No
-Yes, a slightly larger angle will decrease the travel time.    
-Yes, a slightly larger angle will increase the travel time

Explanation / Answer

ni = 1.0
i = 34.2°

n2 = 1.99
r = ?

(a)
Using Snell's Law,
ni * sin(i) = nr * sin(r)
1.0 * sin(34.2) = 1.99 * sin(r)
r = 16.4o

Angle of incidence at the bottom surface = Angle of refraction at the top surface, r = 16.4o

(b)
At the bottom surface,
Using Snell's Law,
1.99 * sin(16.4) = 1.0 * sin()
= 34.2o

(c)
tan(16.4) = x/2.0
tan(34.2) = x'/2.0

x' - x = 2.0 * [tan(34.2) - tan(16.4) ]
x' - x = 0.771 cm

sin(90 - 34.2) = d/0.771
d = 0.638 cm

(d)
Speed of light in glass, v = c/n
v = (3.0*10^8)/(1.99)
v = 1.51 * 10^8 m/s

4 parts allowed per post !!

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