13.1
13.2
13.3
13.4
Calculations
100
What are electromagnetic waves?
A wave that consists of oscillating electric & magnetic waves, which radiate outward from the source at the speed of light
100
Give an application of a flat mirror, concave mirror & convex mirror.
Mirror in a bathroom; dentist mirror; side mirror on car
100
What type of images form from concave mirrors? What type of images form from convex mirrors?
Concave mirrors can form real or virtual images depending on where the object is placed with respect to the mirror. Convex mirrors only form virtual images.
100
What are the additive primary colors? When these combine in equal proportions, what is produced?
Red, blue & green. When all combine in equal proportions, white light is produced
100
The compound eyes of bees and other insects are highly sensitive to light in the ultraviolet portion of the spectrum. One of the frequencies is 7.5E14 Hz. What is the wavelength of this light?
4.0E-7 m
200
How fast do electromagnetic waves travel? All of them?
3.00E8 m/s (300,000,000 m/s); yes all travel at the same speed
200
What is the difference between diffuse & specular reflection? Draw a diagram of both.
Diffusely reflected light is reflected in many directions while specularly reflected light is reflected in the same forward direction.
200
What are the 3 rules to drawing ray diagrams?
1) Parallel to the principal axis, then through the focal point. 2) Through the focal point, then back parallel to the principal axis. 3) Through the center of curvature and back along that same line.
200
Explain why a red corvette appears red under white light.
All colors except red are absorbed. Red light is reflected.
200
Calculate the illuminance of 105 cd light source that is 50.5 cm away.
412 cd/m2
300
Which type of electromagnetic wave would radar fall under?
Microwave
300
In a flat mirror, describe the image that is seen (real or virtual; inverted or upright; reduced, same size or magnified). If a person is 25 cm from the mirror, how far away would their image be from the mirror? How far would the image be from the person?
Virtual, upright, same size. The image is 25 cm from the mirror, but 50 cm away from the person.
300
Draw a ray diagram of an object that is on the focal point and in front of a CONCAVE mirror. Describe the image that forms.
No image forms!
300
Explain how our eyes see color.
Each cone cell is sensitive to red, blue or green light which will combine to produce all the colors in the spectrum. Rod cells are sensitive to the brightness of the light.
300
In the photometer lab, a standard bulb is 65.4 cd and is 70.7 cm away. If an unknown bulb is 34.5 cm away, calculate the intensity of the unknown bulb.
15.6 cd
400
What happens to the illuminance of a light source as your move farther from it?
The illuminance decreases as the radius (distance) is squared when you move away from a light source
400
What is the difference between a real image and a virtual image?
Real images form when the light rays actually pass through a point on an image, while virtual images form from a point where light rays appear to come together.
400
Draw a ray diagram of an arrow that is in front of a CONVEX mirror. Describe the image that forms.
Image is virtual, upright & reduced.
400
What are subtractive primary colors?
These colors rely on colors of light that are absorbed (or subtracted) from the incoming light.
400
A CONCAVE shaving mirror has a radius of curvature of 25.0 cm. A person is 45.0 cm away from the mirror. Calculate the image distance and magnification. Is the image real or virtual and upright or inverted?
q = 17.3 cm; M = -0.384; image is real & inverted.
500
Which wave in the electromagnetic spectrum has the lowest frequency? Which color in the visible light spectrum has the shortest wavelength?
Radio; violet
500
Explain the law of reflection, draw a diagram including labels for the angle of incidence, angle of reflection, normal line & reflecting surface.
When incoming light hits a flat reflecting surface, the angle of incidence equals the angle of reflection.
500
Draw a ray diagram of an arrow that is in front of a CONCAVE mirror and is placed between the center of curvature and the focal point. Describe the image that forms.
Image is real, inverted & magnified.
500
Explain how polarized sunglasses work.
Light reflected off of a hood of a car is horizontally polarized and is filtered out by a polarizing sense whose axis is oriented vertically.
500
A CONVEX mirror has a focal length of 22.5 cm. A person is looking into the mirror and is 14.2 cm away. Calculate the image distance from the mirror and magnification. Is the image real or virtual and upright or inverted?
q = -8.71 cm; M = 0.613; image is virtual & upright
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