Instructions
Read each question carefully and answer to the best of your ability. For multiple-choice questions, circle the letter of the best answer. For other questions, write your answer in the space provided.
Part A: Objective Questions
- What is the phenomenon of light bouncing off a surface called?
- a) Refraction
- b) Absorption
- c) Reflection
- d) Dispersion
- Which of the following surfaces would cause regular (specular) reflection?
- a) A piece of paper
- b) A wooden desk
- c) A calm lake
- d) A woolly sweater
- True or False: The imaginary line drawn perpendicular (at 90°) to a reflecting surface at the point of incidence is called the normal.
- According to the second law of reflection, the angle of incidence is _________ the angle of reflection.
- a) greater than
- b) less than
- c) equal to
- d) double
- An image that cannot be formed on a screen is called a _________ image.
- What type of image is formed by a standard flat mirror (a plane mirror)?
- a) Real and inverted
- b) Virtual and inverted
- c) Real and erect
- d) Virtual and erect
- True or False: Diffuse reflection occurs on rough or uneven surfaces.
- The image formed in a plane mirror is always:
- a) Smaller than the object
- b) The same size as the object
- c) Larger than the object
- d) Upside-down
- The effect where the left side of an object appears as the right side in its mirror image is called _________.
- True or False: We can see non-luminous objects, like a chair, because they reflect light into our eyes.
- A ray of light that strikes the surface of a mirror is called the:
- a) Reflected ray
- b) Normal ray
- c) Incident ray
- d) Refracted ray
- The angle of incidence is the angle measured between the incident ray and the _________.
- a) mirror surface
- b) reflected ray
- c) normal
- d) image
- True or False: A sheet of sandpaper would be an excellent surface for creating a clear reflection.
- The reflection of light from a very smooth, polished surface is called _________ reflection.
- If you stand 2 meters in front of a plane mirror, how far behind the mirror does your image appear to be?
- a) 1 meter
- b) 2 meters
- c) 4 meters
- d) 0.5 meters
- True or False: A real image can be projected onto a screen.
- Which of the following is NOT a characteristic of an image formed by a plane mirror?
- a) The image is virtual.
- b) The image is the same size as the object.
- c) The image is laterally inverted.
- d) The image is real.
- True or False: The Moon produces its own light, which is why we can see it.
- The incident ray, the reflected ray, and the _________ all lie in the same plane.
- What type of reflection allows you to read a book from any position?
- a) Regular reflection
- b) Specular reflection
- c) Diffuse reflection
- d) Total internal reflection
Part B: Subjective Questions
- What is the reflection of light?
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- State the two laws of reflection.
1. __________________________________________________________________________________
2. __________________________________________________________________________________
- What is the main difference between regular reflection and diffuse reflection?
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- Explain why the word "AMBULANCE" is often written in reverse on the front of emergency vehicles.
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- List three characteristics of the image formed by a plane mirror.
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- Can you see a clear image of yourself in a piece of wood? Explain why or why not, using the concept of reflection.
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- What is the difference between a real image and a virtual image?
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- Describe the four key components you would include when diagramming the reflection of a light ray from a mirror.
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- If you are standing 1 meter away from a plane mirror, what is the distance between you and your image? Explain your answer.
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- Why can't you see your reflection in a mirror if the room is completely dark?
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Part C: Problem-Solving
- A ray of light strikes a plane mirror. If the angle of incidence is 35°, what is the angle of reflection?
Answer: _____________________________________________________________________________
- A light ray hits a mirror. The angle between the incident ray and the reflected ray is 80°. What is the angle of incidence?
Answer: _____________________________________________________________________________
- A light ray strikes a plane mirror making an angle of 20° with the surface of the mirror. What is the angle of reflection? (Hint: The angle of incidence is measured from the normal, not the mirror surface).
Answer: _____________________________________________________________________________
- If a light ray strikes a mirror along the normal (perpendicular to the mirror), what will be the value of the angle of reflection?
Answer: _____________________________________________________________________________
- A laser beam is aimed at a plane mirror. The angle between the incoming beam and the mirror surface is 60°. What is the angle between the reflected beam and the normal?
Answer: _____________________________________________________________________________
Answer Key
Part A: Objective Questions
- c) Reflection
- c) A calm lake
- True
- c) equal to
- virtual
- d) Virtual and erect
- True
- b) The same size as the object
- lateral inversion
- True
- c) Incident ray
- c) normal
- False
- regular (or specular)
- b) 2 meters
- True
- d) The image is real.
- False (It reflects sunlight.)
- normal
- c) Diffuse reflection
Part B: Subjective Questions
- Reflection of light is the process where light bounces back after striking a surface.
- 1. The incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.
2. The angle of incidence (∠i) is equal to the angle of reflection (∠r). - Regular reflection occurs on smooth surfaces (like a mirror) where parallel incident rays are reflected as parallel rays, forming a clear image. Diffuse reflection occurs on rough surfaces where parallel incident rays are scattered in many different directions, not forming a clear image.
- It is written in reverse due to lateral inversion. Drivers looking in their rearview mirrors will see the word correctly spelled as "AMBULANCE" and know to give way.
- Any three of: The image is virtual, erect (upright), the same size as the object, laterally inverted, and the image distance equals the object distance.
- No, you cannot see a clear image. Wood has a rough surface that causes diffuse reflection, scattering the light in all directions instead of reflecting it back uniformly to form an image.
- A real image can be projected onto a screen and is formed where light rays actually converge (meet). A virtual image cannot be projected onto a screen and is formed where light rays appear to diverge from.
- 1. Incident Ray: The incoming ray of light. 2. Reflected Ray: The ray of light that has bounced off the surface. 3. Normal: The line drawn perpendicular to the mirror surface at the point of incidence. 4. Angles: The angle of incidence (between incident ray and normal) and the angle of reflection (between reflected ray and normal).
- The distance is 2 meters. Your distance from the mirror is 1 meter, and your image's distance behind the mirror is also 1 meter. The total distance between you and your image is 1 m + 1 m = 2 m.
- To see a reflection, there must be a light source. Light from the source hits you, reflects off you, then travels to the mirror, reflects off the mirror, and finally enters your eyes. Without any light, this process cannot happen.
Part C: Problem-Solving
- The angle of reflection is 35°. (According to the law of reflection, angle of incidence = angle of reflection).
- The angle of incidence is 40°. (The total angle is 80°, which is the angle of incidence + the angle of reflection. Since they are equal, each must be 80° / 2 = 40°).
- The angle of reflection is 70°. (The angle of incidence is measured from the normal. The normal is at 90° to the mirror. So, the angle of incidence = 90° - 20° = 70°. The angle of reflection is equal to the angle of incidence).
- The angle of reflection is 0°. (When a ray strikes along the normal, the angle of incidence is 0°. Therefore, the angle of reflection is also 0°, and the ray bounces straight back along the same path).
- The angle between the reflected beam and the normal is 30°. (The angle of incidence is 90° - 60° = 30°. The angle of reflection is equal to the angle of incidence, so it is also 30°).