10 Questions
What is the angle of the reflected ray compared to the angle of the incident ray?
Equal to the angle of the incident ray
Why can we see illuminated surfaces from any position?
Because of diffuse reflection
What happens to light when it encounters a boundary between two transparent media?
A portion of it is reflected and a portion is transmitted
In what plane is the reflected ray always found?
The plane defined by the incident ray and the normal to the surface
Why do mirrors produce clear images, but most natural surfaces do not?
Because mirrors are smooth, but natural surfaces are rough
What is the relationship between the angle of incidence and the angle of refraction, according to Snell's law?
n1 sin θ1 = n2 sin θ2
What is the index of refraction of a medium?
The ratio of the speed of light in a vacuum to its speed in the medium
What happens to light during refraction?
It changes direction and medium
What is the key difference between reflection and refraction?
Reflection is the act of light reflecting back, while refraction is the process of light shifting its path
What is the relationship between the angle of incidence and the angle of reflection?
The angle of incidence is equal to the angle of reflection
Study Notes
Light Rays and Their Behaviors
- Light rays change direction when they reflect off a surface, move from one transparent medium into another, or travel through a medium whose composition is continuously changing.
Law of Reflection
- States that, on reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray.
- Angles are measured with respect to the normal to the surface (a line perpendicular to the surface).
- The reflected ray is always in the plane defined by the incident ray and the normal to the surface.
Mirrors and Diffuse Reflection
- Plane and curved mirrors produce images that can be understood using the law of reflection.
- Most natural surfaces are rough on the scale of the wavelength of light, causing parallel incident light rays to be reflected in many different directions (diffuse reflection).
- Diffuse reflection allows us to see most illuminated surfaces from any position.
Refraction
- Occurs when light traveling in one transparent medium encounters a boundary with a second transparent medium (e.g., air and glass).
- A portion of the light is reflected, and a portion is transmitted into the second medium.
- As transmitted light moves into the second medium, it changes its direction of travel (refraction).
- Law of Refraction (Snell's Law): n1 sin θ1 = n2 sin θ2, where n1 and n2 are the indices of refraction of the first and second media, respectively.
Index of Refraction
- A dimensionless constant equal to the ratio of the speed of light in a vacuum to its speed in a medium.
Key Differences between Reflection and Refraction
- Reflection: Light rebounds after hitting a surface (e.g., mirrors).
- Refraction: Light shifts its path as it travels through a material, causing the light to bend (e.g., lenses).
Reflection vs. Refraction
- Reflection: Occurs on a plane, with the light entering the medium returning to the same medium.
- Refraction: Occurs when light passes through a surface, changing direction and medium.
Understand how light rays behave when they reflect off a surface or travel through different mediums. Learn about the law of reflection and how angles are measured in geometrical optics.
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