Interview Questions.

Q1. Define Space-peak Ratio?

It is defined as the ratio of horizontal distance between adjoining lamps and peak in their mountings.

Space-peak ratio = [Horizontal distance between two adjacent lamps] / [Mounting height of lamps above working plane]

Q2. What Are All The Sources Of Light?

As according to the precept of operation the light sources can be grouped as follows:

Arc lamps

High temperature Lamps

Gaseous Discharge Lamps

Fluorescent kind Lamps

Q3. Define Luminous Flux?

It is described as the whole amount of mild power emitted per second from a luminous frame. 

It is represented by means of symbol F and is measured in lumens. 

The theory of luminous flux enables us to specify the output and efficiency of a given mild supply.

Q4. Define Mhcp?

The mean of candle energy in all guidelines in the horizontal aircraft containing the source of mild is termed as Mean Horizontal Candle Power.

Q5. What Are The Laws Of Illumination?

Law of Inverse squares:

Illumination at a factor is inversely proportional to rectangular of its distance from the factor supply and at once proportional to the luminous intensity (CP) of the source of light in that course.

If a source of light which emits light similarly in all instructions be located at the centre of a hole sphere, the light will fall uniformly on the internal floor of the sector. 

If the field be replaced by using one of the larger radius, the equal general amount of mild is unfold over a bigger vicinity proportional to the square of the radius.

Lambert’s cosine regulation:

The illumination at a point on a surface is proportional to cosine of the angle which ray makes with the ordinary to the normal to the floor at that point.

Q6. Define Utilization Factor?

It is defined as the ratio of overall lumens accomplishing the working plane to total lumens given out by using the lamp

utilisation issue  = [Total lumens reaching the working plane] / [Total lumens given out by the lamp]

Q7. What Is Meant By Candle Power?

It is defined because the variety of lumens given out by using the supply in a unit stable perspective in a given course. 

It is denoted by way of CP

Cp = lumens /ω

Q8. What Is Meant By Luminance?

It is defined as the luminous consistent with unit projected area of either a surface source of mild or a reflecting surface and is denoted through L.

Q9. What Is Polar Curve?

In most lamps or assets of mild the luminous intensity is not the same in all directions. 

If the luminous depth, ie, the candle strength is measured in a horizontal aircraft about a vertical axis and a curve is plotter between candle power and the angular role, a curve obtained is referred to as as horizontal polar curve.

The luminous depth in all of the guidelines can be represented via polar curves. 

If the luminous depth in a vertical aircraft is plotted against position, a curve called vertical polar curve.

Q10. Name The Various Photometer Heads?

Bunsen head or Grease spot photometer

Lummer-brodhun photometer head

There are  varieties of lummer brodhun heads:

Equality oc Brightness type photometer head

Contrast kind photometer head