Lighting

Question 1

What is the visible light spectrum span?

Answer 1

350nm to 750nm

Question 2

What is Luminous intensity?

Answer 2

This is the power of the light source to emit light flux in a particular direction

Question 3

What is the unit used to measure luminous intensity?

Answer 3

candela (cd) pronounced “can dee la”

Question 4

What is candela (cd) used to measure?

Answer 4

Luminous intensity

Question 5

What is the symbol for candela?

Answer 5

ɪ

Question 6

What does the symbol “ ɪ “ represent?

Answer 6

Candela, for luminous intensity.

Question 7

What is luminous flux?

Answer 7

Luminous flux is the rate of flow of light energy from a source.

Question 8

What is the unit for luminous flux?

Answer 8

Lumen (lm)

Question 9

What is does unit lumen (lm) represent?

Answer 9

Luminous flux

Question 10

What is the symbol for luminous flux?

Answer 10

Φ of F.

Question 11

What does the symbols Φ and F represent in lighting?

Answer 11

Luminous flux

Question 12

What is illuminance?

Answer 12

Illuminance is the amount of light energy reaching a surface.

Question 13

What is the unit for illuminance?

Answer 13

The unit for illuminance is Lux (lx) or Lm/m² and its symbol is E

Question 14

How do you calculate illuminance?

Answer 14

Illuminance = Luminous flux
————
area

Or

E = F (Φ)
——
A

Question 15

What illuminance level is emergency lighting rated at?

Answer 15

A minimum of 0.2 lux

Question 16

What illuminance level is bright sunlight rated at?

Answer 16

Approximately 50,000 Lux.

Question 17

What is the difference between luminous flux and illuminance?

Answer 17

Illuminance measured the light at the surface whereas luminous flux measures the flow of light from the source.