Exercise: Reflection, Geometrical Optics, physics 10
E - 1. The diagram shows a curved surface. Draw normals to the surface at the marked points.

E - 2. In the diagram, label the following:
(a) normal

(b) angle of incidence
(c) angle of reflection
(d) incident ray
(e) reflected ray


E - 3. State the Law of Reflection. Draw a diagram, label the appropriate angles and write a mathematical expression for the Law of Reflection.

E - 4. Draw a ray diagram to show the relationship between the angle of incidence and the angle of reflection.

E - 5. The diagram shows an incident ray I . Which of the other 5 rays (A, B, C, D, E) best represents the reflected ray of I ?


E - 6. A ray of light strikes a surface at 15◦ to the surface normal. Draw a ray diagram showing the incident ray, reflected ray and surface normal. Calculate the angles of incidence and reflection and fill them in on your diagram.

E - 7. A ray of light leaves a surface at 45◦ to the surface normal. Draw a ray diagram showing the incident ray, reflected ray and surface normal. Calculate the angles of incidence and reflection and fill them in on your diagram.

E - 8. A ray of light strikes a surface at 25◦ to the surface. Draw a ray diagram showing the incident ray, reflected ray and surface normal. Calculate the angles of incidence and reflection and fill them in on your diagram.

E - 9. A ray of light leaves a surface at 65◦ to the surface. Draw a ray diagram showing the incident ray, reflected ray and surface normal. Calculate the angles of incidence and reflection and fill them in on your diagram.

E - 10. If the incident ray, the reflected ray and the surface normal do not fall on the same plane, will the angle of incidence equal the angle of reflection?

E - 11. Explain the difference between specular and diffuse reflection.

E - 12. We see an object when the light that is reflected by the object enters our eyes. Do you think the reflection by most objects is specular reflection or diffuse reflection? Explain.

E - 13. A beam of light (for example from a torch) is generally not visible at night, as it travels through air. Try this for yourself. However, if you shine the torch through dust, the beam is visible. Explain why this happens.

E - 14. If a torch beam is shone across a classroom, only students in the direct line of the beam would be able to see that the torch is shining. However, if the beam strikes a wall, the entire class will be able to see the spot made by the beam on the wall. Explain why this happens.

E - 15. A scientist looking into a flat mirror hung perpendicular to the floor cannot see her feet but she can see the hem of her lab coat. Draw a ray diagram to help explain the answers to the following questions:
(a) Will she be able to see her feet if she backs away from the mirror?
(b) What if she moves towards the mirror?

Xem thêm:
Physics 10.VI Geometrical Optics

High School Students Studying the Sciences Physics