Question 1

Taxiway lights at most airports are blue because

Accepted Answer

Blue appears brighter in dim light, making it easier for pilots to see taxiways during low light conditions such as dusk or dawn.

Question 2

Trichromatic theory states that there are three kinds of _____ in the eye.

Accepted Answer

Trichromatic theory states that there are three types of color-sensitive cones in the eye that respond to different wavelengths of light: blue, green, and red. This theory explains how humans are able to perceive a wide range of colors by combining and interpreting the signals received from these three types of cones.

Question 3

As a teacher writes on the board, she detects over her shoulder a student about to throw a wad of paper at her.This excellent peripheral vision is due to the large concentration of _____ in the periphery of her eyes.

Accepted Answer

Rods are photoreceptor cells in the eye that are responsible for vision in low-light conditions and are concentrated in the periphery of the retina. Due to their sensitivity to light, they allow for better peripheral vision, which can aid in detecting movements or objects in the peripheral visual field, such as the student about to throw the paper wad. Cones, on the other hand, are responsible for color vision and are concentrated in the central part of the retina. Phosphenes are the visual sensations of lights or colors that are not actually present and are often experienced as a result of pressure or stimulation of the eye or brain. Stereocilia are not found in the eyes but are hair-like structures in the ear that help with hearing.

Question 4

In daylight, which color becomes relatively brighter?

Accepted Answer

Yellow-green is one of the colors that reflects more light in daylight, making it appear relatively brighter compared to other colors.

Question 5

Your best friend is trying to sneak up on you, but you note some movement coming up behind you on your left side.You spin around and scare her instead.Your ability to detect the movement demonstrates your excellent _____ vision, which is due to the large number of _____ that lie about 20 degrees from the center of the retina.

Accepted Answer

The ability to detect movement on the left side indicates peripheral vision, which is best served by rods. Rods are more sensitive to low-level light and are located about 20 degrees from the center of the retina, outside the area of the macula where cones, responsible for color vision, are concentrated. Therefore, options A and B are incorrect. Option D refers to hair cells in the cochlea, which are not relevant to vision.

Question 6

Which theory of color vision holds that there are three types of cones that respond to red, green, and blue?

Accepted Answer

The trichromatic theory, also known as the Young-Helmholtz theory, proposes that there are three types of cones in the human retina that respond to different wavelengths of light, corresponding to the colors red, green, and blue. These colors can be mixed to create any other color in the visible spectrum.

Question 7

Seeing "out of the corner of your eye" is important in sports activities and driving.This is known as

Accepted Answer

Peripheral vision allows you to see objects and movement outside of your direct line of sight, which is important in sports activities and driving. Tunnel vision refers to a narrowed field of vision, astigmatism is a vision condition that causes blurred vision, and feature detection is a cognitive process in which the brain identifies specific objects within a visual scene.

Question 8

At night or under low illumination conditions, visual acuity is best when

Accepted Answer

Using the rods in the eye allows for better vision in low illumination conditions due to their high sensitivity to light. The fovea is responsible for high visual acuity but is less effective in low light conditions. The color of objects viewed does not significantly affect night vision, and viewing with only one eye may reduce depth perception but does not improve visual acuity in low light.

Question 9

You have experienced damage to a large number of rods in the periphery of your eye and feel like you are wearing blinders with no vision to the left and right sides.You are suffering from

Accepted Answer

Tunnel vision is the narrowing of the visual field, causing a person to only be able to see straight ahead and not to the sides. Damage to the rods in the periphery of the eye could cause this. Myopia and hyperopia refer to refractive errors and retinitis refers to inflammation of the retina.

Question 10

Which person has the best visual acuity?

Accepted Answer

Ian has the best visual acuity with 20/12 vision, indicating that he can see at a distance of 20 feet what the average person can see at a distance of 12 feet.

Question 11

An air-traffic controller is trying to spot the lights of an airplane on the horizon at night.He should look

Accepted Answer

The air-traffic controller should look next to where he thinks the airplane is, rather than directly at it. This is because the airplane's lights can be more difficult to spot when looking directly at them due to the way our eyes perceive light in the night sky. Looking just next to where the airplane is, allows the controller's peripheral vision to pick up on the airplane's lights more easily. Additionally, it's always best to use both eyes when looking for something in the distance, rather than just one. The controller should also allow some time for his eyes to adjust to the darkness before starting to look for the airplane, rather than looking at a bright light to preadapt his eyes.

Question 12

Damage to the receptors for peripheral vision could be expected to create

Accepted Answer

Damage to the receptors for peripheral vision, specifically the rods located in the outer areas of the retina, could result in tunnel vision. This is because the rods are responsible for detecting movement and objects in the peripheral fields. Without them, individuals may only be able to see objects in a narrow, central area of their visual field. Higher visual acuity, blindness, and color blindness are not associated with damage to peripheral vision receptors.

Question 13

The cones are more sensitive to the _____ part of the spectrum, while the rods are more sensitive to _____.

Accepted Answer

Cones are most sensitive to the yellow-green part of the spectrum, which is crucial for color vision in bright light. Rods are more sensitive to the blue-green part of the spectrum, which is important for vision in low light conditions.

Question 14

Areas outside the fovea also get light creating a large region of _____ vision, which involves mainly the _____ of the eye.

Accepted Answer

The areas outside the fovea are part of the peripheral vision, which is mainly served by the rods in the eye. The cones, responsible for color vision, are mostly concentrated in the central fovea. Additionally, the iris controls the amount of light entering the eye, but it doesn't directly contribute to vision itself. Therefore, option C is the correct answer.

Question 15

Many fire trucks are yellow-green rather than red because

Accepted Answer

Yellow-green colors are easier to see in daylight compared to red. This is important for fire trucks, as they need to be noticeable on the road to alert other drivers and pedestrians. The color yellow is also associated with caution, which further emphasizes the importance of fire trucks on the road.

Question 16

You have been feverishly playing a new video game for an hour.All of sudden you hear a familiar voice to your right side.You are startled to discover that your best friend has been standing there watching you for five minutes.You have experienced temporary

Accepted Answer

Tunnel vision is a condition where peripheral vision is lost, and only the central vision is retained. In this scenario, the intense focus on the video game likely caused a temporary narrowing of attention, leading to a lack of awareness of the surroundings, including the presence of the friend.

Question 17

If you worked on a road maintenance crew, you would want to wear a _____ vest so that you could be most easily seen during the day.

Accepted Answer

Yellow is the color commonly used for high visibility safety vests, and is recommended by the Federal Highway Administration for road maintenance crews.

Question 18

Police and highway patrol cars in many states have blue emergency lights for night work because the _____ in the eye are more sensitive to blue or blue-green light in dim light.

Accepted Answer

The rods in the eye are more sensitive to blue or blue-green light in dim light, hence police and highway patrol cars in many states have blue emergency lights for night work.

Question 19

Sam is being administered a test known as the Landolt rings.Sam's _____ is being assessed.

Accepted Answer

The Landolt rings are a test used to assess visual acuity, which is the ability to distinguish details and visual sharpness. The test presents the patient with a ring with a gap, and they must indicate the direction of the gap. This assesses their ability to discriminate details and perceive sharpness of vision.

Question 20

At low levels of illumination, looking next to an object rather than directly at it would produce

Accepted Answer

Looking next to an object rather than directly at it is called using peripheral vision. At low levels of illumination, the center of the retina (where acute vision occurs) is less sensitive than the peripheral areas of the retina. Therefore, using peripheral vision can provide improved acuity in low light conditions, but color discrimination is poorer in peripheral vision compared to direct vision.

Quiz 4: Extension A: Sensation and Reality