# Refrecation of light Lab

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Introduction
OBJECTIVES
The transmission of light across a boundary between two media is
accompanied by a change in both the speed and wavelength of the
wave.
This can result in a change of direction at the boundary, a
phenomenon known as refraction.
In this experiment you measure the change in direction of light
beams as they refract or reflect at a boundary to determine the index
of refraction of a transparent object.
The objectives of this experiment are as follows:
1. To measure the angles of incidence and refraction at a
boundary between media
2. To observe total internal reflection at a boundary between
media
3. To calculate the critical angle of a boundary between media
Theory Part 1
WHAT IS REFRACTION?
Refraction is the bending of light.
This occurs when light travels through one material to another (ex:
air, water, etc…)
For example, when looking at a glass of water with a straw in it, the
straw may appear to be broken.
This happens because light moves more slowly in water than in air.
As a result, the light bends as it passes from air to water, making the
straw appear to be bent.
Mathematically, Snell's law describes the relationship between the
angle of incidence of a beam of light as it intersects a new
transparent medium and the angle of refraction as enters that
transparent medium.
Snell's law quantifies the relationship that is observed in above:
n1∙ sin θ1 = n2∙ sin θ2
where n1 is the index of refraction of medium 1, n2 is the index of
refraction medium 2, θ1 is the angle that the light ray makes with
respect to the normal in medium 1, θ2 is the angle that the light ray
makes with respect to the normal in medium 2.
Theory Part 2
When the angle of incidence from denser medium to a lighter
medium reaches a certain critical value, the refracted ray lies along
the boundary, having an angle of refraction of 90-degrees.
This angle of incidence is known as the critical angle;
It is the largest angle of incidence for which refraction can still occur.
For any angle of incidence greater than the critical angle, light will
undergo total internal reflection.
Note that this only happens for light traveling from a denser
medium to a lighter one
The equation for the critical angle is:
Where,
θc
n2
n1
Question 1 (1 point)
Saved
The critical angle.
Refraction index.
Incident index.
What is Refraction?
Question 1 options:
The reflection of light.
The color change of light.
The bending of light.
The frequency change of light.
Question 2 (1 point)
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What is the critical angle?
Question 2 options:
The angle of incidence for which the angle of refraction is 45&deg;.
The angle for which light stop travelling.
The angle of refraction for which the angle of incidence is 90&deg;.
The angle of incidence for which the angle of refraction is 90&deg;.
Question 3 (1 point)
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What is the accepted value for the index of refraction in air?
Question 3 options:
n = 1.33
n = 0.75
n = 1.00
n = 0.00
Question 4 (1 point)
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When light moves from a low index of refraction to a higher index of
refraction, light will bend:
Question 4 options:
Away from the normal.
Not enough information is provided to answer this question.
Have no change.
Towards the normal.
Question 5 (1 point)
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When light enters at an angle of 90&deg; to the surface (boundary
between the mediums), the angle of reflection will be?
Question 5 options:
0&deg;
Not enough information is provided to answer this question.
Towards the normal.
Away from the normal.
Question 6 (1 point)
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100% of the intensity of light will always be transmitted from
medium 1 into medium 2?
Question 6 options:
True
False
Question 7 (1 point)
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The bending of light as it moves from one medium to another with
differing indices of refraction is due to a change in what property of
the light?
Question 7 options:
amplitude
frequency
speed
color
Question 8 (1 point)
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A beam of light passes from air into water.
Which of the following statements is true?
Question 8 options:
a) Both the wavelength and frequency decrease.
b) The frequency is unchanged and the wavelength increases.
c) Both the wavelength and frequency increase.
d) The frequency is unchanged and the wavelength decreases.
e) The wavelength is unchanged and the frequency decreases.
Question 9 (1 point)
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A scuba diver shines a flashlight from beneath the surface of water
(n = 1.33) such that the light strikes the water-air boundary with an
angle of incidence of 43&deg;.
At what angle is the beam refracted?
Question 9 options:
a) 31&deg;
b) 43&deg;
c) 90&deg;
d) 48&deg;
e) 65&deg;
Question 10 (1 point)
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A ray of light propagates in water (n = 1.333) and strikes a sheet of
crown glass (n = 1.523).
If the angle of refraction in the glass is 35.2&deg;, determine the angle of
incidence.
Question 10 options:
a) 41.2&deg;
b) 35.2&deg;
c) 30.3&deg;
d) 32.8&deg;
e) 45.0&deg;
Question 11 (1 point)
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Which one of the following expressions determines the critical angle
for quartz (n = 1.5) immersed in oil (n = 1.1)?
Question 11 options:
a) sin (1.1/1.5)
b) tan-1 (1.1/1.5)
c) 1.1/1.5
d) sin-1 (1.1/1.5)
e) sin-1 (1.5/1.1)
Question 12 (1 point)
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A ray of light originates in medium A and is incident upon medium B.
For which one of the following pairs of indices of refraction
for A and B is total internal reflection not possible?
Question 12 options:
a) nA = 1.12
nB = 1.06
b) nA = 2.54
nB = 1.63
c) nA = 1.26
nB = 1.15
d) nA = 1.36
nB = 1.00
e) nA = 1.28
nB = 1.36
Submit Quiz12 of 12 questions saved
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