Parts of the eye Flashcards
(13 cards)
How can you experimentally determine the difference between the focal lengths of a shiny spoon and a shiny metal teaspoon?
Direct parallel light rays into the concave side. Measure the distance between the point where the rays converge, that is the focal length.
What will be the image position and magnification from a convex mirror with focal length = -10 cm when an object is located 90 cm from the mirror?
Image position (di) = -9 cm, Magnification (M) = 0.1
Why is the type of material crucial to the function of optical cables?
Total internal reflection must occur in these cables to trap the light energy so it can travel long distances. For TIR to occur, the inside material must be denser than the outer material.
How can you determine whether a clear, colorless rock is quartz or glass using the index of refraction?
Since the index of refraction of glass (n = 1.52) is larger than that of quartz (n = 1.46), light should bend closer to the normal in glass than in quartz.
Is the following statement true or false? The normal is always drawn at a 90° angle to the mirror or lens.
True
Is the following statement true or false? When light is reflected from a curved mirror, the angle of incidence is twice the angle of reflection.
False. The angle of incidence is always equal to the angle of reflection.
Is the following statement true or false? Concave (diverging) lenses always produce virtual images while convex (converging) lenses always produce real images.
False. Diverging lenses always form virtual images; however, converging lenses can form both real and virtual images.
Is the following statement true or false? A magnification of +2 means the object is upright and double the height of the object.
True
What type of lenses do ‘reading glasses’ typically use?
Converging lenses. Hyperopia is when a person cannot see close up because the image forms behind the retina. Converging lenses cause rays to converge so the image forms sooner, landing on the retina.
What type of mirror would you expect to find in a telescope?
Concave mirrors, since they focus light and magnify images.
Why is it sometimes difficult to reach a coin that is underwater in a pond?
Light rays bend when they pass from water to air, making the coin appear at a different location than it actually is.
How does a fiber optic cable transmit information using light?
Fiber optics use total internal reflection. They are made of a material that is optically dense, then coated with a cladding that has a low optical density. This difference causes the cable to have a very low critical angle, ensuring that the angle of incidence nearly always exceeds this critical angle, resulting in reflection.
What are the differences between refraction and reflection as ways to change the direction of a light ray?
Refraction involves the bending of light as it passes from one medium to another, while reflection involves the bouncing of light off a surface. The laws of refraction are described by Snell’s Law, while the law of reflection states that the angle of incidence equals the angle of reflection.
