Law of reflection, Snell's law, total internal reflection, dispersion, mirrors
How can I study Reflection and Refraction effectively?โพ
Start by reading the study notes and working through the examples on this page. Then use the flashcards to test your recall. Practice with the 15 problems provided, checking solutions as you go. Regular review and active practice are key to retention.
Is this Reflection and Refraction study guide free?โพ
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What course covers Reflection and Refraction?โพ
Reflection and Refraction is part of the AP Physics 2 course on Study Mondo, specifically in the Optics section. You can explore the full course for more related topics and practice resources.
Are there practice problems for Reflection and Refraction?
ฮป
frequency
f
c=ฮปf
Visible spectrum: 400 nm (violet) to 700 nm (red)
Law of Reflection
When light reflects from smooth surface:
ฮธiโ=ฮธrโ
Angle of incidence = Angle of reflection
Angles measured from normal (perpendicular to surface).
Center ray (through C) โ reflects back on itself
Where rays intersect = image location!
Problem-Solving Strategy
Snell's Law:
Draw diagram with normal
Identify nโ, ฮธโ, nโ
Apply: n1โsinฮธ1โ=n2โsinฮธ2โ
Check for TIR if going to less dense medium
Mirrors:
Identify f (positive for concave, negative for convex)
Use mirror equation: 1/f=1/doโ+1/diโ
Find magnification: m=โdiโ/doโ
Interpret signs
Common Mistakes
โ Measuring angles from surface instead of normal
โ Forgetting to check for total internal reflection
โ Wrong sign for f (convex mirrors have negative f!)
โ Confusing d_i sign (positive = real/front, negative = virtual/behind)
โ Thinking frequency changes during refraction (only v and ฮป change!)
โ Using degrees instead of checking calculator mode
Check: Entering denser medium (nโ > nโ), so bends toward normal. โ
ฮธโ = 22.1ยฐ < ฮธโ = 30ยฐ โ
Answer: ฮธโ = 22.1ยฐ (bends toward normal)
2Problem 2easy
โ Question:
Light travels from air (n = 1.00) into water (n = 1.33) at an angle of 30ยฐ from the normal. What is the angle of refraction?
๐ก Show Solution
Given:
Medium 1 (air): n1โ=1.00
Medium 2 (water): n2โ=1.33
Incident angle: ฮธ1โ=30ยฐ
Solution:
Apply Snell's Law:
n1โsinฮธ1โ=n2โ
Check: Entering denser medium (nโ > nโ), so bends toward normal. โ
ฮธโ = 22.1ยฐ < ฮธโ = 30ยฐ โ
Answer: ฮธโ = 22.1ยฐ (bends toward normal)
3Problem 3easy
โ Question:
Light travels from air (n = 1.00) into water (n = 1.33) at an angle of 30ยฐ from the normal. What is the angle of refraction?
๐ก Show Solution
Given:
Medium 1 (air): n1โ=1.00
Medium 2 (water): n2โ=1.33
Incident angle: ฮธ1โ=30ยฐ
Solution:
Apply Snell's Law:
n1โsinฮธ1โ=n2โ
Check: Entering denser medium (nโ > nโ), so bends toward normal. โ
ฮธโ = 22.1ยฐ < ฮธโ = 30ยฐ โ
Answer: ฮธโ = 22.1ยฐ (bends toward normal)
4Problem 4easy
โ Question:
Light travels from air (n = 1.00) into water (n = 1.33) at an angle of 30ยฐ from the normal. What is the angle of refraction?
๐ก Show Solution
Given:
Medium 1 (air): n1โ=1.00
Medium 2 (water): n2โ=1.33
Incident angle: ฮธ1โ=30ยฐ
Solution:
Apply Snell's Law:
n1โsinฮธ1โ=n2โ
Check: Entering denser medium (nโ > nโ), so bends toward normal. โ
ฮธโ = 22.1ยฐ < ฮธโ = 30ยฐ โ
Answer: ฮธโ = 22.1ยฐ (bends toward normal)
5Problem 5easy
โ Question:
Light travels from air (n = 1.00) into water (n = 1.33) at an angle of 30ยฐ from the normal. What is the angle of refraction?
๐ก Show Solution
Given:
Medium 1 (air): n1โ=1.00
Medium 2 (water): n2โ=1.33
Incident angle: ฮธ1โ=30ยฐ
Solution:
Apply Snell's Law:
n1โsinฮธ1โ=n2โ
Check: Entering denser medium (nโ > nโ), so bends toward normal. โ
ฮธโ = 22.1ยฐ < ฮธโ = 30ยฐ โ
Answer: ฮธโ = 22.1ยฐ (bends toward normal)
6Problem 6medium
โ Question:
What is the critical angle for light going from glass (n = 1.50) to air (n = 1.00)? What happens at 45ยฐ incidence?
๐ก Show Solution
Given:
Medium 1 (glass): n1โ=1.50
Medium 2 (air): n2โ=1.00
Part 1: Critical angle
sinฮธcโ=n1โ
Part 2: At 45ยฐ incidence
Since 45ยฐ>ฮธcโ=41.8ยฐ, we have total internal reflection!
Light reflects completely back into glass. No refraction into air.
Answer:
Critical angle: ฮธ_c = 41.8ยฐ
At 45ยฐ: Total internal reflection (no light exits to air)
This is why fiber optic cables work - light trapped inside!
7Problem 7medium
โ Question:
What is the critical angle for light going from glass (n = 1.50) to air (n = 1.00)? What happens at 45ยฐ incidence?
๐ก Show Solution
Given:
Medium 1 (glass): n1โ=1.50
Medium 2 (air): n2โ=1.00
Part 1: Critical angle
sinฮธcโ=n1โ
Part 2: At 45ยฐ incidence
Since 45ยฐ>ฮธcโ=41.8ยฐ, we have total internal reflection!
Light reflects completely back into glass. No refraction into air.
Answer:
Critical angle: ฮธ_c = 41.8ยฐ
At 45ยฐ: Total internal reflection (no light exits to air)
This is why fiber optic cables work - light trapped inside!
8Problem 8medium
โ Question:
What is the critical angle for light going from glass (n = 1.50) to air (n = 1.00)? What happens at 45ยฐ incidence?
๐ก Show Solution
Given:
Medium 1 (glass): n1โ=1.50
Medium 2 (air): n2โ=1.00
Part 1: Critical angle
sinฮธcโ=n1โ
Part 2: At 45ยฐ incidence
Since 45ยฐ>ฮธcโ=41.8ยฐ, we have total internal reflection!
Light reflects completely back into glass. No refraction into air.
Answer:
Critical angle: ฮธ_c = 41.8ยฐ
At 45ยฐ: Total internal reflection (no light exits to air)
This is why fiber optic cables work - light trapped inside!
9Problem 9medium
โ Question:
What is the critical angle for light going from glass (n = 1.50) to air (n = 1.00)? What happens at 45ยฐ incidence?
๐ก Show Solution
Given:
Medium 1 (glass): n1โ=1.50
Medium 2 (air): n2โ=1.00
Part 1: Critical angle
sinฮธcโ=n1โ
Part 2: At 45ยฐ incidence
Since 45ยฐ>ฮธcโ=41.8ยฐ, we have total internal reflection!
Light reflects completely back into glass. No refraction into air.
Answer:
Critical angle: ฮธ_c = 41.8ยฐ
At 45ยฐ: Total internal reflection (no light exits to air)
This is why fiber optic cables work - light trapped inside!
10Problem 10medium
โ Question:
What is the critical angle for light going from glass (n = 1.50) to air (n = 1.00)? What happens at 45ยฐ incidence?
๐ก Show Solution
Given:
Medium 1 (glass): n1โ=1.50
Medium 2 (air): n2โ=1.00
Part 1: Critical angle
sinฮธcโ=n1โ
Part 2: At 45ยฐ incidence
Since 45ยฐ>ฮธcโ=41.8ยฐ, we have total internal reflection!
Light reflects completely back into glass. No refraction into air.
Answer:
Critical angle: ฮธ_c = 41.8ยฐ
At 45ยฐ: Total internal reflection (no light exits to air)
This is why fiber optic cables work - light trapped inside!
11Problem 11hard
โ Question:
A concave mirror has focal length 20 cm. An object is placed 60 cm from the mirror. Find (a) image distance, (b) magnification, (c) describe the image.
๐ก Show Solution
Given:
Focal length: f=20 cm (positive for concave)
Object distance: doโ=60 cm
Part (a): Image distance
Mirror equation:
f1โ=doโ
Part (b): Magnification
m=โdoโdiโ
Part (c): Image description
diโ>0: Real image (in front of mirror)
m<0: Inverted
: (half size)
Answer:
(a) d_i = 30 cm (in front)
(b) m = -0.50
(c) Real, inverted, reduced to half size
12Problem 12hard
โ Question:
A concave mirror has focal length 20 cm. An object is placed 60 cm from the mirror. Find (a) image distance, (b) magnification, (c) describe the image.
๐ก Show Solution
Given:
Focal length: f=20 cm (positive for concave)
Object distance: doโ=60 cm
Part (a): Image distance
Mirror equation:
f1โ=doโ
Part (b): Magnification
m=โdoโdiโ
Part (c): Image description
diโ>0: Real image (in front of mirror)
m<0: Inverted
: (half size)
Answer:
(a) d_i = 30 cm (in front)
(b) m = -0.50
(c) Real, inverted, reduced to half size
13Problem 13hard
โ Question:
A concave mirror has focal length 20 cm. An object is placed 60 cm from the mirror. Find (a) image distance, (b) magnification, (c) describe the image.
๐ก Show Solution
Given:
Focal length: f=20 cm (positive for concave)
Object distance: doโ=60 cm
Part (a): Image distance
Mirror equation:
f1โ=doโ
Part (b): Magnification
m=โdoโdiโ
Part (c): Image description
diโ>0: Real image (in front of mirror)
m<0: Inverted
: (half size)
Answer:
(a) d_i = 30 cm (in front)
(b) m = -0.50
(c) Real, inverted, reduced to half size
14Problem 14hard
โ Question:
A concave mirror has focal length 20 cm. An object is placed 60 cm from the mirror. Find (a) image distance, (b) magnification, (c) describe the image.
๐ก Show Solution
Given:
Focal length: f=20 cm (positive for concave)
Object distance: doโ=60 cm
Part (a): Image distance
Mirror equation:
f1โ=doโ
Part (b): Magnification
m=โdoโdiโ
Part (c): Image description
diโ>0: Real image (in front of mirror)
m<0: Inverted
: (half size)
Answer:
(a) d_i = 30 cm (in front)
(b) m = -0.50
(c) Real, inverted, reduced to half size
15Problem 15hard
โ Question:
A concave mirror has focal length 20 cm. An object is placed 60 cm from the mirror. Find (a) image distance, (b) magnification, (c) describe the image.
๐ก Show Solution
Given:
Focal length: f=20 cm (positive for concave)
Object distance: doโ=60 cm
Part (a): Image distance
Mirror equation:
f1โ=doโ
Part (b): Magnification
m=โdoโdiโ
Part (c): Image description
diโ>0: Real image (in front of mirror)
m<0: Inverted
: (half size)
Answer:
(a) d_i = 30 cm (in front)
(b) m = -0.50
(c) Real, inverted, reduced to half size
โพ
Yes, this page includes 15 practice problems with detailed solutions. Each problem includes a step-by-step explanation to help you understand the approach.