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Test Prep

Multiple Choice

15.1The Electromagnetic Spectrum

1.

Which type of EM radiation has the shortest wavelengths?

1. gamma rays
2. infrared waves
3. blue light
4. microwaves
2.

Which form of EM radiation has the most penetrating ability?

1. red light
2. microwaves
3. gamma rays
3.
Why are high-frequency gamma rays more dangerous to humans than visible light?
1. Gamma rays have a lower frequency range than visible light.
2. Gamma rays have a longer wavelength range than visible light.
3. Gamma rays have greater energy than visible light for penetrating matter.
4. Gamma rays have less energy than visible light for penetrating matter.
4.
A dog would have a hard time stalking and catching a red bird hiding in a field of green grass. Explain this in terms of cone cells and color perception.
1. Dogs are red-green color-blind because they can see only blue and yellow through two kinds of cone cells present in their eyes.
2. Dogs are only red color-blind because they can see only blue and yellow through two kinds of cones cells present in their eyes.
3. Dogs are only green color-blind because they can see only blue and yellow through two kinds of cones cells present in their eyes.
4. Dogs are color-blind because they have only rods and no cone cells present in their eyes.

5.

To compare the brightness of light bulbs for sale in a store, you should look on the labels to see how they are rated in terms of ____.

1. frequency
2. watts
3. amps
4. lumens
6.

What is the wavelength of red light with a frequency of 7.50 × 1014 Hz?

1. 2.50 × 1014 m
2. 4.00 × 10−15 m
3. 2.50 × 106 m
4. 4.00 × 10−7 m
7.

What is the distance of one light year in kilometers?

1. 2.59 × 1010 km
2. 1.58 × 1011 km
3. 2.63 × 109 km
4. 9.46 × 1012 km
8.

How does the illuminance of light change when the distance from the light source is tripled? Cite the relevant equation and explain how it supports your answer.

1. if distance is tripled, then the illuminance increases by 19 times.
2. if distance is tripled, then the illuminance decreases by 13 times.
3. if distance is tripled, then the illuminance decreases by nine times.
4. if distance tripled, then the illuminance increases by 3 times.
9.

A light bulb has an illuminance of 19.9 lx at a distance of 2 m . What is the luminous flux of the bulb?

1. 500 lm
2. 320 lm
3. 250 lm
4. 1,000 lm

15.1The Electromagnetic Spectrum

10.

Describe one way in which heat waves—infrared radiation—are different from sound waves.

1. Sound waves are transverse waves, whereas heat waves—infrared radiation—are longitudinal waves.
2. Sound waves have shorter wavelengths than heat waves.
3. Sound waves require a medium, whereas heat waves—infrared radiation—do not.
4. Sound waves have higher frequencies than heat waves.
11.
Describe the electric and magnetic fields that make up an electromagnetic wave in terms of their orientation relative to each other and their phases.
1. They are perpendicular to and out of phase with each other.
2. They are perpendicular to and in phase with each other.
3. They are parallel to and out of phase with each other.
4. They are parallel to and in phase with each other.
12.
Explain how X-radiation can be harmful and how it can be a useful diagnostic tool.
1. Overexposure to X-rays can cause HIV, though normal levels of X-rays can be used for sterilizing needles.
2. Overexposure to X-rays can cause cancer, though in limited doses X-rays can be used for imaging internal body parts.
3. Overexposure to X-rays causes diabetes, though normal levels of X-rays can be used for imaging internal body parts.
4. Overexposure to X-rays causes cancer, though normal levels of X-rays can be used for reducing cholesterol in the blood.
13.
Explain how sunlight is the original source of the energy in the food we eat.
1. Sunlight is converted into chemical energy by plants; this energy is released when we digest food.
2. Sunlight is converted into chemical energy by animals; this energy is released when we digest food.
3. Sunlight is converted into chemical energy by fish; this energy is released when we digest food.
4. Sunlight is converted into chemical energy by humans; this energy is released when we digest food.

14.
Describe what happens to the path of light when the light slows down as it passes from one medium to another?
1. The path of the light remains the same.
2. The path of the light becomes circular.
3. The path of the light becomes curved.
4. The path of the light changes direction.
15.
What is it about the nature of light reflected from snow that causes skiers to wear polarized sunglasses?
1. The reflected light is polarized in the vertical direction.
2. The reflected light is polarized in the horizontal direction.
3. The reflected light has less intensity than the incident light.
4. The reflected light has triple the intensity of the incident light.
16.

How many lumens are radiated from a candle which has an illuminance of 3.98 lx at a distance of 2.00 m?

1. 400 lm
2. 100 lm
3. 50 lm
4. 200 lm
17.

Saturn is 1.43×1012 m from the Sun. How many minutes does it take the Sun’s light to reach Saturn?

1. 7.94 × 109 minutes
2. 3.4 × 104 minutes
3. 3.4 × 10–6 minutes
4. 79.4 minutes

Extended Response

15.1The Electromagnetic Spectrum

18.

A frequency of red light has a wavelength of 700 nm.

Part A—Compare the wavelength and frequency of violet light to red light.

Part B—Identify a type of radiation that has lower frequencies than red light.

Part C—Identify a type of radiation that has shorter wavelengths than violet light.
1. Violet light has a lower frequency and longer wavelength than red light.
1. Violet light has a lower frequency and longer wavelength than red light.
1. Violet light has a higher frequency and shorter wavelength than red light.
1. Violet light has a higher frequency and shorter wavelength than red light.
19.

A mixture of red and green light is shone on each of the subtractive colors.

Part A—Which of these colors of light are reflected from magenta?

Part B—Which of these colors of light are reflected from yellow?

Part C—Which these colors of light are reflected from cyan?
1. Part A. red and green

Part B. green

Part C. red
2. Part A. red and green

Part B. red

Part C. green
3. Part A. green

Part B. red and green

Part C. red
4. Part A. red

Part B. red and green

Part C. green

20.

Explain why we see the colorful effects of thin-film interference on the surface of soap bubbles and oil slicks, but not on the surface of a window pane or clear plastic bag.

1. The thickness of a window pane or plastic bag is more than the wavelength of light, and interference occurs for thicknesses smaller than the wavelength of light.
2. The thickness of a window pane or plastic bag is less than the wavelength of light, and interference occurs for thicknesses similar to the wavelength of light.
3. The thickness of a window pane or plastic bag is more than the wavelength of light, and interference occurs for thicknesses similar to the wavelength of light.
4. The thickness of a window pane or plastic bag is less than the wavelength of light, and interference occurs for thicknesses larger than the wavelength of light.
21.
The Occupational Safety and Health Administration (OSHA) recommends an illuminance of $500lx$ for desktop lighting. An office space has lighting hung $2.50m$ above desktop level that provides only $300lx$. To what height would the lighting fixtures have to be lowered to provide $500lx$ on desktops?
1. $1.22m$
2. $1.09m$
3. $0.96m$
4. $1.94m$