Index of Refraction - AP Physics 2
Card 1 of 36
The speed of light in a vacuum, 
, is calculated to be 
. The speed of light in a diamond is calculated to be 
. What is the refractive index of diamond?
The speed of light in a vacuum, 
Tap to reveal answer
The definition of refractive index of a medium 
is the speed of light in a vacuum divided by the speed of light in the medium:
We have values for 
and 
, so we can plug in our numbers into the equation.
Because we're dividing two values with the same units, our answer is unitless.
The definition of refractive index of a medium
We have values for
Because we're dividing two values with the same units, our answer is unitless.
← Didn't Know|Knew It →
What is the speed at which light travels through the water?
and 
What is the speed at which light travels through the water?
Tap to reveal answer
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
← Didn't Know|Knew It →
A beam of light travelling through air enters a transparent material at an angle of incidence at 
, with the refracted beam's angle being 
. What is the index of refraction of the material? Assume the index of refraction of air is 1.
A beam of light travelling through air enters a transparent material at an angle of incidence at
Tap to reveal answer
To find the index of refraction given two angles and another index of refraction, we use Snell's law.
We can plug in the numbers we have to find the answer.
Simplifying, we get:
To find the index of refraction given two angles and another index of refraction, we use Snell's law.
We can plug in the numbers we have to find the answer.
Simplifying, we get:
← Didn't Know|Knew It →
A beam of light travelling through air enters a medium with an index of refraction of 
and goes through it at an angle of 
. What is the angle of incidence?
Assume the index of refraction of air is 1.
A beam of light travelling through air enters a medium with an index of refraction of
Assume the index of refraction of air is 1.
Tap to reveal answer
To find the angle of incidence, we use Snell's law.
We're given both indices of refraction, and the second angle, so we can plug in our numbers.
Therefore, the angle of incidence is 
.
To find the angle of incidence, we use Snell's law.
We're given both indices of refraction, and the second angle, so we can plug in our numbers.
Therefore, the angle of incidence is
← Didn't Know|Knew It →
An argon/krypton laser puts out green light at 
. It takes 
to travel through 
of honey. What is the index of refraction of the honey?
An argon/krypton laser puts out green light at
Tap to reveal answer
First off we can find the velocity of the laser beam since we know the distance of honey it travels through and the transit time.
However, this doesn't need to be explicitly solved for. The velocity of light inside a material is inversely proportional to the index of refraction of that material where
where 
is the speed of light in vacuum. Setting these equal, we can solve for the index of refraction of the honey.
We expect that the index of refraction will be greater than that of air and a velocity less than 
.
First off we can find the velocity of the laser beam since we know the distance of honey it travels through and the transit time.
However, this doesn't need to be explicitly solved for. The velocity of light inside a material is inversely proportional to the index of refraction of that material where
where
We expect that the index of refraction will be greater than that of air and a velocity less than
← Didn't Know|Knew It →
The speed of light through a particular material is measured to be 
, calculate the index of refraction of the material.
The speed of light through a particular material is measured to be
Tap to reveal answer
The speed of light passing through a medium is given by:
Rearrange to solve for the index of refraction and plug in numbers.
The speed of light passing through a medium is given by:
Rearrange to solve for the index of refraction and plug in numbers.
← Didn't Know|Knew It →
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly 
to the surface of alcohol.
Determine the index of refraction of alcohol if the light ray bends to 
to the normal. Assume index of refraction of air is 
.
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly
Determine the index of refraction of alcohol if the light ray bends to
Tap to reveal answer
We can use our knowledge about the indices of refraction to come up with our equation:
, where 
is the index of refraction of air and 
is the index of refraction for our alcohol.
Since 
We can use our knowledge about the indices of refraction to come up with our equation:
Since
← Didn't Know|Knew It →
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly 
to the surface of alcohol.
Determine the index of refraction required in the alcohol to have total internal reflection?
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly
Determine the index of refraction required in the alcohol to have total internal reflection?
Tap to reveal answer
To have total internal reflection, our equation will become:
To have total internal reflection, our equation will become:
← Didn't Know|Knew It →
Suppose that a ray of light traveling through air strikes a new medium. Upon doing so, the light bends away from the normal. Which of the following could this new medium be?
Suppose that a ray of light traveling through air strikes a new medium. Upon doing so, the light bends away from the normal. Which of the following could this new medium be?
Tap to reveal answer
For this question, we're told that light is passing from air into another medium. In doing so, the light is refracted such that it bends away from the normal. We're asked to identify a possible medium.
The most important thing to understand about refraction is that when light passes into a new medium at an angle with respect to the normal, that light will be refracted, either away from or toward the normal. This is because light will travel through different media at different speeds. The faster light travels, the more it will bend away from the normal.
Generally, the angle at which light is bent can be predicted by Snell's law. In doing so, this equation takes use of the refractive index, a value unique to each medium. The expression for refractive index is as follows.
Where 
refers to the refractive index, 
refers to the speed of light in a vacuum, and 
refers to the speed of light in a given medium.
Since the speed of light is fastest when in a vacuum, the refractive index can never be less than 
. Only when the light is in a vacuum is the refractive index equal to 
. In any other medium, the refractive index will be greater than 
, even if it is slight.
Light will always refract away from the normal when it passes into a medium with a lower refractive index (indicating the light is traveling faster). Starting from air, the only way this can happen is for the new medium to have an index of refraction that is less than air. Of the answer choices shown, the only one that fits that criteria is the vacuum.
For this question, we're told that light is passing from air into another medium. In doing so, the light is refracted such that it bends away from the normal. We're asked to identify a possible medium.
The most important thing to understand about refraction is that when light passes into a new medium at an angle with respect to the normal, that light will be refracted, either away from or toward the normal. This is because light will travel through different media at different speeds. The faster light travels, the more it will bend away from the normal.
Generally, the angle at which light is bent can be predicted by Snell's law. In doing so, this equation takes use of the refractive index, a value unique to each medium. The expression for refractive index is as follows.
Where
Since the speed of light is fastest when in a vacuum, the refractive index can never be less than
Light will always refract away from the normal when it passes into a medium with a lower refractive index (indicating the light is traveling faster). Starting from air, the only way this can happen is for the new medium to have an index of refraction that is less than air. Of the answer choices shown, the only one that fits that criteria is the vacuum.
← Didn't Know|Knew It →
The speed of light in a vacuum, , is calculated to be . The speed of light in a diamond is calculated to be . What is the refractive index of diamond?
The speed of light in a vacuum,
Tap to reveal answer
The definition of refractive index of a medium is the speed of light in a vacuum divided by the speed of light in the medium:
We have values for and , so we can plug in our numbers into the equation.
Because we're dividing two values with the same units, our answer is unitless.
The definition of refractive index of a medium
We have values for
Because we're dividing two values with the same units, our answer is unitless.
← Didn't Know|Knew It →
What is the speed at which light travels through the water?
and
What is the speed at which light travels through the water?
Tap to reveal answer
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
← Didn't Know|Knew It →
A beam of light travelling through air enters a transparent material at an angle of incidence at , with the refracted beam's angle being . What is the index of refraction of the material? Assume the index of refraction of air is 1.
A beam of light travelling through air enters a transparent material at an angle of incidence at
Tap to reveal answer
To find the index of refraction given two angles and another index of refraction, we use Snell's law.
We can plug in the numbers we have to find the answer.
Simplifying, we get:
To find the index of refraction given two angles and another index of refraction, we use Snell's law.
We can plug in the numbers we have to find the answer.
Simplifying, we get:
← Didn't Know|Knew It →
A beam of light travelling through air enters a medium with an index of refraction of and goes through it at an angle of . What is the angle of incidence?
Assume the index of refraction of air is 1.
A beam of light travelling through air enters a medium with an index of refraction of
Assume the index of refraction of air is 1.
Tap to reveal answer
To find the angle of incidence, we use Snell's law.
We're given both indices of refraction, and the second angle, so we can plug in our numbers.
Therefore, the angle of incidence is .
To find the angle of incidence, we use Snell's law.
We're given both indices of refraction, and the second angle, so we can plug in our numbers.
Therefore, the angle of incidence is
← Didn't Know|Knew It →
An argon/krypton laser puts out green light at . It takes to travel through of honey. What is the index of refraction of the honey?
An argon/krypton laser puts out green light at
Tap to reveal answer
First off we can find the velocity of the laser beam since we know the distance of honey it travels through and the transit time.
However, this doesn't need to be explicitly solved for. The velocity of light inside a material is inversely proportional to the index of refraction of that material where
where is the speed of light in vacuum. Setting these equal, we can solve for the index of refraction of the honey.
We expect that the index of refraction will be greater than that of air and a velocity less than .
First off we can find the velocity of the laser beam since we know the distance of honey it travels through and the transit time.
However, this doesn't need to be explicitly solved for. The velocity of light inside a material is inversely proportional to the index of refraction of that material where
where
We expect that the index of refraction will be greater than that of air and a velocity less than
← Didn't Know|Knew It →
The speed of light through a particular material is measured to be , calculate the index of refraction of the material.
The speed of light through a particular material is measured to be
Tap to reveal answer
The speed of light passing through a medium is given by:
Rearrange to solve for the index of refraction and plug in numbers.
The speed of light passing through a medium is given by:
Rearrange to solve for the index of refraction and plug in numbers.
← Didn't Know|Knew It →
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly to the surface of alcohol.
Determine the index of refraction of alcohol if the light ray bends to to the normal. Assume index of refraction of air is .
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly
Determine the index of refraction of alcohol if the light ray bends to
Tap to reveal answer
We can use our knowledge about the indices of refraction to come up with our equation:
, where is the index of refraction of air and is the index of refraction for our alcohol.
Since
We can use our knowledge about the indices of refraction to come up with our equation:
Since
← Didn't Know|Knew It →
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly to the surface of alcohol.
Determine the index of refraction required in the alcohol to have total internal reflection?
You are passing a ray of light through clear alcohol to determine properties. You shine the light ray exactly
Determine the index of refraction required in the alcohol to have total internal reflection?
Tap to reveal answer
To have total internal reflection, our equation will become:
To have total internal reflection, our equation will become:
← Didn't Know|Knew It →
Suppose that a ray of light traveling through air strikes a new medium. Upon doing so, the light bends away from the normal. Which of the following could this new medium be?
Suppose that a ray of light traveling through air strikes a new medium. Upon doing so, the light bends away from the normal. Which of the following could this new medium be?
Tap to reveal answer
For this question, we're told that light is passing from air into another medium. In doing so, the light is refracted such that it bends away from the normal. We're asked to identify a possible medium.
The most important thing to understand about refraction is that when light passes into a new medium at an angle with respect to the normal, that light will be refracted, either away from or toward the normal. This is because light will travel through different media at different speeds. The faster light travels, the more it will bend away from the normal.
Generally, the angle at which light is bent can be predicted by Snell's law. In doing so, this equation takes use of the refractive index, a value unique to each medium. The expression for refractive index is as follows.
Where refers to the refractive index, refers to the speed of light in a vacuum, and refers to the speed of light in a given medium.
Since the speed of light is fastest when in a vacuum, the refractive index can never be less than . Only when the light is in a vacuum is the refractive index equal to . In any other medium, the refractive index will be greater than , even if it is slight.
Light will always refract away from the normal when it passes into a medium with a lower refractive index (indicating the light is traveling faster). Starting from air, the only way this can happen is for the new medium to have an index of refraction that is less than air. Of the answer choices shown, the only one that fits that criteria is the vacuum.
For this question, we're told that light is passing from air into another medium. In doing so, the light is refracted such that it bends away from the normal. We're asked to identify a possible medium.
The most important thing to understand about refraction is that when light passes into a new medium at an angle with respect to the normal, that light will be refracted, either away from or toward the normal. This is because light will travel through different media at different speeds. The faster light travels, the more it will bend away from the normal.
Generally, the angle at which light is bent can be predicted by Snell's law. In doing so, this equation takes use of the refractive index, a value unique to each medium. The expression for refractive index is as follows.
Where
Since the speed of light is fastest when in a vacuum, the refractive index can never be less than
Light will always refract away from the normal when it passes into a medium with a lower refractive index (indicating the light is traveling faster). Starting from air, the only way this can happen is for the new medium to have an index of refraction that is less than air. Of the answer choices shown, the only one that fits that criteria is the vacuum.
← Didn't Know|Knew It →
The speed of light in a vacuum, , is calculated to be . The speed of light in a diamond is calculated to be . What is the refractive index of diamond?
The speed of light in a vacuum,
Tap to reveal answer
The definition of refractive index of a medium is the speed of light in a vacuum divided by the speed of light in the medium:
We have values for and , so we can plug in our numbers into the equation.
Because we're dividing two values with the same units, our answer is unitless.
The definition of refractive index of a medium
We have values for
Because we're dividing two values with the same units, our answer is unitless.
← Didn't Know|Knew It →
What is the speed at which light travels through the water?
and
What is the speed at which light travels through the water?
Tap to reveal answer
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
Write the formula relating the speed of light, velocity of light in specific medium, and index of refraction of the medium.
Rewrite the equation so that we are solving for the velocity of light in water. Substitute given values.
← Didn't Know|Knew It →