Important Questions with Answers

ANNA UNIVERSITY Part - A '2' Marks Q & A

1. What is visual field glare?

Glare is difficulty of seeing in the presence of bright light such as sunlight or artificial light (car head lamps at night). Because of this, some cars include mirrors with automatic with  anti-glare functions.

2. What are types of glare?

(i) Direct glare

(ii) Reflected glare

(iii) Disability

(iv) Discomfort glare

 (v) Distract glare

3. What are the reducing factors of visibility?

• Reduction of brightness of the rest of the scence by constriction of the pupils.

• Reduction in contrast of the rest of the scence by scattering of the bright light within the eye.

• Reduction in contrast by scattering light in particles in the air.

• Bloom surrounding objects infront of glare.

• Reduction in contrast by reflection of bright areas on the surface of a transparent medium or glass, plastic or water.

4. What are the methods to reduce glare?

(i) Sunglasses are often wore to reduce glare. The polarized sunglasses are designed to reduce glare caused by light reflected from non-metallic surfaces such as water, glossy printed matter or painted surfaces.

(ii) An anti-reflective treatment of an eyeglass reduces the glare at night and glare from inside lights and computer screens.

5. What is daylight?

Daylight, or the light of day, is the combination of all direct and indirect sunlight during the day time. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by the earth and terrestrial objects (landforms and buildings).

6. What is daylight factor?

The daylight factor is defined as:

where

E_i - illuminance due to daylight at a point on the indoors working plane.

E_o - simultaneous outdoor illuminance on a horizontal plane from an unobstructed

hemisphere of overcast sky

7. What is the use of models in daylight calculation?

Model studies can be used to predict daylight penetration into any building. This is the only reliable prediction method in the case of unusual situations, complex geometries or heavily obstructed windows.

Model studies can be carried out under outdoor conditions, but the limitations imposed by weather variations can be quite severe.

The artificial sky simulates the standard overcast sky conditions, giving uniform luminance.

8. What are the forms of artificial sky?

There are two basic forms of artificial sky:

(i) hemispherical and

(ii) rectangular

9. Mention few artificial light sources.

1. Incandescent lamp

2. Fluorescent tube

3. Compact fluorescent lamp

4. Discharge lamps

5. Light Emitting Diode (LED)

ANNA UNIVERSITY Part B (16 Marks) Questions

1. Write notes on

(a) visual field glare

(b) day light calculation

(c) daylight factor

2. Discuss daylight design of windows.

3. Describe principles of artificial lighting and supplementary