CLD Lighting Fundamentals 4

Question 1

What is the spectral power distribution (SPD) of a light source?

Accepted Answer

A graph showing radiant power emitted at each wavelength across the visible spectrum

Answer

An SPD curve shows how the radiant power of a light source is distributed across each wavelength of the visible (and adjacent) spectrum.

Question 2

A retail display luminaire is specified with a narrow beam angle. What effect does this have on the target?

Accepted Answer

Higher center-beam candlepower and concentrated illuminance

Answer

A narrower beam angle concentrates luminous intensity into a smaller solid angle, resulting in higher center-beam candlepower and more focused, high illuminance on the target.

Question 3

What is 'adaptation' in the context of the human visual system?

Accepted Answer

The process by which the eye adjusts its sensitivity to different luminance levels

Answer

Visual adaptation is the process by which the eye adjusts its sensitivity (via pupil dilation and photoreceptor response) to match prevailing luminance conditions.

Question 4

In lighting design, what does 'task-ambient ratio' refer to?

Accepted Answer

The ratio of task illuminance to general (ambient) illuminance in a space

Answer

The task-ambient ratio compares the illuminance level on the work surface to the surrounding ambient light level, affecting visual comfort and energy efficiency.

Question 5

Which of the following best describes 'photopic luminosity function' (V(λ))?

Accepted Answer

The spectral sensitivity of the human eye under bright (photopic) conditions, peaking near 555 nm

Answer

The photopic luminosity function V(λ) describes the relative sensitivity of the light-adapted human eye to different wavelengths, peaking at approximately 555 nm (green-yellow).

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Lighting Fundamentals 4