Lecture questions Flashcards
Specular reflection is…
a type of surface reflectance often described as the mirror-like reflection of light from a surface in a single direction
Diffuse reflection is…
when light is reflected from a surface in many different directions
Reflection
the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
Or, when light bounces off of a surface instead of traveling through it
Refraction
the change in direction of a wave passing from one medium to another caused by its change in speed
or, when a beam of light travels from through one medium and into another
When n1 < n2, what happens to a refracted beam of light? Imagine a ray of light traveling from air into glass.
it is bent towards the normal
v1 > v2
theta1 > theta2
when n1 > n2, what happens to a refracted ray of light? Imagine a ray of light traveling from glass into air.
it is bent away from the normal
v1 < v2
theta1 < theta2
The theory proposing light as a particle is supported by…
The photoelectric effect discovered by hertz (the emission of electrons when electromagnetic radiation hits a material)
A ray of light hits a flat surface at an angle theta and is diffusely reflected. At what angle is it reflected?
unknown (in diffuse reflection light is reflected in all directions)
As light travels from vaccum (n=1) to a medium such as glass (n>1), which of the following will remain the same? (wavelength, wave speed, and frequency)
only frequency will remain the same
Light passes from a material with an index of refraction of 1.1 into one with an index of refraction of 1.5 after being incident at a non-normal angle. Compared to the incident ray, the refracted ray will..
bend towards the normal
When a beam of white light is refracted through a prism, which of the following colors has the greatest angular deviation from the original direction of the beam?
purple
Two people observe an object in front of a flat mirror. The first person is to the left of the object and the second views it from straight on. The second person sees the image of the object directly behind the mirror. Where does the first person see the image of the object?
directly behind the mirror
How can you tell where the image is based on a ray diagram?
The image occurs where all of the rays cross eachother
A real image is always located on the _____ side of the mirror as the object, while a virtual image is always on the ____ side
same, opposite
How can you tell that an image will be inverted based on a ray diagram?
The order of the rays will be reversed when they are reflected off the mirror
What are the rules for drawing a ray diagram?
- ray 1 (blue) is drawn parallel to the principal (x) axis and is reflected back through the focal point (f)
- ray 2 (green) is drawn through the focal pont and is reflected parallel to the principal axis (x)
- ray 3 (red) is drawn through the center of curvature and is reflected back on itself
to summarize:
1. parallel -> F
2. F -> parallel
3. C -> C again
For a concave mirror, what do we know about the image when the center of curvature, C is between the object and the surface of the mirror?
the image is real, inverted, and reduced in size
For a concave mirror, what do we know about the image when the object is located between the focal point and the mirror surface (very close to the mirror)
the image is virtual. upright, and enlarged
What do we know about the focal point, center of curvature, and image for a convex mirror?
The focal point and center of curvature will always be behind the mirror. The image is always virtual, upright, and reduced in size.
What is the difference between a virtual image and a real image?
A virtual image appears to be located where no light rays intersect, whereas a real image exists where light rays actually intersect
the virtual image is behind the mirror, the real image is in front of the mirror
the image created by a flat mirror is….
virtual with magnification M=1
A mirror creates an image of an object. It is upright, and appears to be slightly smaller than the object itself. What kind of mirror is it?
Convex
A person spearfishing from a boat sees a fish located 3m from the boat at an apparent depth of 1m. To spear the fish, the person should aim…
below the image of the fish
What are the steps for drawing a ray diagram for a thin lens?
- ray 1 (blue) is drawn parallel to the principal axis. After being refracted, it passes through one of the focal points
- Ray 2 (red) is drawn through the center of the lens and continues in a straight line
- Ray 3 (green) is drawn through the other focal point and emerges from the lens parallel to the principal (X) axis
or
1. parallel -> focal point
2. straight through the center
3. focal point -> parallel
A clear plastic sandwich bag filled with air is submerged in water. The lens that is created is….
diverging
True or false? An object is placed to the left of a converging lens. The image is always to the right.
False
True or false? An object is placed to the left of a converging lens. The image can be upright or inverted.
True
True or false? An object is placed to the left of a converging lens. The image is always smaller or the same size as the object.
False
If the distance between the slits is double in young’s experiment, what happens to the width of the central maximum?
The width is halved
the screen locations of the dark fringes of order m are given by ydarkm=(lamdaL/d)(m+1/2). m=0 corresponds to the first dark fringe on either side of the central maximum. The width of the central maximum is found by 2ydark=lambdaL/d
For interference to occur, which of the following must be true?
The light sources must be in phase and have the same wavelength.
Two campers wish to start a fire during the day. One camper is nearsighted and one is farsighted. Whose glasses should be used to focus the sun’s rays onto some paper to start a fire?
the farsighted camper’s (convex corrective lens)
