Section 6.1: Reflection
Reflection is the bouncing back of light from a surface. The laws of reflection state that:
- The angle of incidence equals the angle of reflection (\( \theta_i = \theta_r \)).
- The incident ray, reflected ray, and normal lie in the same plane.
Reflection occurs on plane and curved surfaces, forming images that can be real or virtual.
Example: Image Formation by a Plane Mirror
An object is placed 10 cm in front of a plane mirror. Find the position of the image.
For a plane mirror, the image distance equals the object distance:
\( d_i = d_o = 10 \, \text{cm behind the mirror} \)
Practice Problems
- A ray strikes a plane mirror at 30°. Find the angle of reflection.
- An object is placed 15 cm in front of a plane mirror. Determine the image location.
- Draw the reflected rays for an incident ray striking a plane mirror at 45°.
- Explain why images in plane mirrors appear virtual.
- A concave mirror has a focal length of 20 cm. Place an object 30 cm in front of it and find the image position using the mirror equation.