Reflection is the bouncing of a wave off a surface and refraction is the change of direction as a wave changes speed, so this IB sheet opens by contrasting the two direction rules. The answers record diffraction as spreading through a gap.
Key Takeaways
Reflection is the bouncing of a wave off a surface (Q1).
Refraction is the change of direction as a wave changes speed (Q2).
Q3 records diffraction as spreading through a gap.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.Reflection is the
(a) bouncing of a wave off a surface(b) bending of a wave(c) spreading of a wave(d) slowing of a wave
2.Refraction is the
(a) change of direction of a wave as it changes speed(b) reflection of a wave(c) absorption of a wave(d) production of a wave
3.Diffraction is the
(a) spreading of a wave as it passes through a gap or around an obstacle(b) bending of light in a prism(c) reflection of sound(d) production of stationary waves
4.The law of reflection states that the angle of incidence equals
(a) the angle of reflection(b) 90°(c) 0°(d) the angle of refraction
5.When light enters a denser medium, it
(a) slows down and bends towards the normal(b) speeds up and bends away from the normal(c) continues in a straight line(d) stops moving
6.Sound waves diffract noticeably through a doorway because
(a) their wavelength is comparable to the size of the gap(b) they travel very fast(c) they are very loud(d) they are longitudinal
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.State the law of reflection.
8.Define refraction.
9.Define diffraction.
10.When does a wave bend towards the normal?
11.Give one example of diffraction of sound.
12.What happens to the speed of light when it enters glass from air?
13.Write the equation for refractive index in terms of the speed of light.
14.What is the normal line in reflection?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.Light strikes a plane mirror with an angle of incidence of 40°. Using the law of reflection, find the angle of reflection.
16.Light travels from air into glass with an angle of incidence of 30° and an angle of refraction of 20°. Using n = sin i ÷ sin r, find the refractive index (sin 30° = 0.5, sin 20° = 0.34).
17.A wave has a frequency of 50 Hz and a wavelength of 2 m. Using v = fλ, find its speed.
18.The speed of light in a vacuum is 3 × 10⁸ m/s and in glass it is 2 × 10⁸ m/s. Using n = c ÷ v, find the refractive index of glass.
19.Light travels at 3 × 10⁸ m/s with a frequency of 5 × 10¹⁴ Hz. Using λ = v ÷ f, find the wavelength.
20.A wave with a wavelength of 0.5 m passes through a gap of width 0.5 m. Describe the amount of diffraction.
Answer Key
1. a) bouncing of a wave off a surface
2. a) change of direction of a wave as it changes speed
3. a) spreading of a wave as it passes through a gap or around an obstacle
4. a) the angle of reflection
5. a) slows down and bends towards the normal
6. a) their wavelength is comparable to the size of the gap
7. Refer to solution guide.
8. Refer to solution guide.
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20. Refer to solution guide.
End of Worksheet
People Also Ask
What is reflection?
The bouncing of a wave off a surface, option (a) in this worksheet (Q1).
What is refraction?
The change of direction of a wave as it changes speed, option (a) in this worksheet (Q2).
What is diffraction?
The spreading of a wave as it passes through a gap or around an obstacle, option (a) in this worksheet (Q3).
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