Light Background

Question 1

What is light?

Answer 1

Electromagnetic radiation spectrum is bookended by ultraviolet (short wavelengths) and infrared (long wavelengths).

Question 2

What is one of the technical groups that influences lighting standards.

Answer 2

Illuminating Engineering Society (IES)

Question 3

What do lighting standards attempt to mitigate?

Answer 3

Eyestrain, headaches, and minimize productivity losses.

Memory Clue: EHP

Question 4

What type of vision do rods assist with? What is the color/wavelength that rods have peak sensitivity to?

Answer 4

Peripheral vision, dim lighting conditions. Peak sensitivity to blue-green light (498 nm).

Question 5

What type of vision do cones assist with? What is the color/wavelength that cones have peak sensitivity to?

Answer 5

Daytime vision, color perception. Peak sensitivity to green-yellow light (555 nm).

Question 6

In what non-visual way does light influence the human body?

Answer 6

Circadian rhythm

Question 7

What are the external cues that align physiological functions to the solar day?

Answer 7

Zeitgerbers

Question 8

Which is the most important Zeitgerber?

Answer 8

Light

Question 9

What is photoentrainment?

Answer 9

The process that keeps the body’s internal clocks synchronized through light cues (zeitgerbers).

Question 10

What are the non-image forming photoreceptors?

Answer 10

Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs)

Question 11

What is the color/wavelength that ipRGCs have peak sensitivity to?

Answer 11

Teal-blue light (approximately 480 nm)

Question 12

What is the most significant part of the brain that Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs) send information to that acts as the main clock in our bodies?

Answer 12

Suprachiasmatic Nucleus

Question 13

What does the Suprachiasmatic Nucleus do with the information from the Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs)?

Answer 13

It acts to synchronize the clocks in the peripheral tissues and organs.

Question 14

What physiological processes are regulated in

part by photoentrainment?

Answer 14

Alertness, digestion, and sleep.

Memory Clue: ADS

Question 15

Per the Institute of Medicine, how many US adults have chronic sleep or wakefulness disorder as a results of light cues in the environment?

Answer 15

50 to 70 million U.S. adults

Question 16

What risks are associated with chronic sleep deprivation?

Answer 16

Depression, diabetes, heart attack, hypertension, obesity, and stroke.

Memory Clue: DDHHOS

Question 17

What is the process of body clock synchronization known as?

Answer 17

Circadian Photoentrainment

Question 18

What types of light contribute to circadian photoentrainment?

Answer 18

All light (not just sunlight)

Question 19

What can lead to a drift of the circadian

phase?

Answer 19

Insufficient illumination or improper lighting design

Question 20

Light exposure in the late night/early morning will shift our rhythms ___.

Answer 20

Forward (phase advance)

Question 21

Exposure in the late afternoon/early night will shift our rhythms ___.

Answer 21

Back (phase delay)

Question 22

Light intensity for visual

acuity is measured in___.

Answer 22

Lux (foot candles)

Question 23

Lux is ___.

Answer 23

A measure of the way the eye responds to light weighted to the response of the cone cells

Question 24

Ambient light levels of ___ lux are sufficient for most tasks.

Answer 24

300

Question 25

Adequate light levels are needed for a broad variety of activities, including ___.

Answer 25

Reading different sizes of print and working on detail oriented tasks.

Question 26

To meet the requirement for Feature 84: Visual Lighting Design, the following must be met

Answer 26

-The ambient lighting system is able to maintain an average light intensity of 215 lux or more, measured on the horizontal work plane. -The ambient lighting system is zoned in independently controlled banks no larger than 500 ft² or 20% of open floor area of the room (whichever is larger). -If average ambient light is below 300 lux, task lights providing 300 to 500 lux at the work surface are available upon request.

Question 27

The biological effects of light on humans can be measured in ___.

Answer 27

Equivalent Melanopic Lux (EML)

Question 28

What is Equivalent Melanopic Lux (EML)?

Answer 28

A proposed alternate metric that is weighted to the ipRGCs instead of to the cones, which is the case with traditional lux.