Electrical

Question 1

1. Location electric outlets along the wall?

Answer 1

1. Every 6 feet. 2. Every 2 feet along kitchen counters.

Question 2

2. How can You reduce the frequency of static shocks in home?

Answer 2

The best remedy is to add moisture to the air with a console or installed humidifier.

Question 3

3. What is the white wire on a 240-volt circuit?

Answer 3

It ia hot and code requires you to mark it with a piece of black tape as a reminder.

Question 4

4. Tape that is used various colors to mark and identify wires?

Answer 4

Colored electric tape.

Question 5

5. A plastic plier designed specifically to remove fuses from electrical boxes?

Answer 5

Fuse puller.

Question 6

What is a Candela?

Answer 6

The unit of measurement of luminous intensity of a light source in a given direction.

Question 7

What is a Lumen?

Answer 7

The unit of luminous flux; the luminous flux emitted within a unit solid angle (one steradian) by a point source having a uniform luminous intensity of one candela (1 cd).

Question 8

What is Illuminance?

Answer 8

The density of the luminous flux incident on a surface; the quotient of the luminous flux divided by the area of the surface when the latter is uniformly illuminated.

Question 9

What is Luminaire efficiency?

Answer 9

The ratio of the light output of a light source (a specific lamp) to the electrical energy consumed to produce that light source.

Question 10

What is Illumination?

Answer 10

Luminous flux in lumens incident on the surface.

Question 11

What is Light life?

Answer 11

The rated life of a lamp is its median life expectancy, expressed in hours. The cumulative time that lapses before 50% of a representative group of lamps has failed and the other lamps in the group continue operating (for most lamp types). For LED sources, the life is defined as the time which lumen output depreciates to 70% of initial value.

Question 12

What is Color Rendering Index?

Answer 12

Measure of the degree of color shift objects undergo when illuminated by a light source, as compared with a reference source, normally incandescent.

Question 13

What is Lumen Maintenance?

Answer 13

How a lamp maintains its light output over its lifetime.

Question 14

What are the Three Principal Lamp Types?

Answer 14

1. Incandescent
2. Fluorescent
3. High-intensity Discharge (HID)

Question 15

What is an Incandescent Lamp?

Answer 15

Incandescent lamps emit visible light as a result of heating; they incandesce.

Question 16

What are Fluorescent Lamps?

Answer 16

Fluorescent lamp is composed of a tubular glass bulb that is covered with a thin phosphor coating on its inside surface.

Question 17

What is a Ballast?

Answer 17

A device used with fluorescent and HID lamps to provide the necessary starting voltage and to limit the current during operation of the lamp.

Question 18

What are High Intensity Discharge Lamps?

Answer 18

High-intensity discharge lamps (HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with noble gas and often also contains suitable metal or metal salts.

Question 19

Lumens Method

Answer 19

The lumens method (also called the zonal cavity method) is a way to calculate the average illuminance (light level) in a room or space. It’s widely used in lighting design when you want to size lighting systems for offices, classrooms, warehouses, et

Question 20

Point Method

Answer 20

The point method (often called the point-by-point method) is another approach in lighting design, but instead of estimating the average light in a whole room (like the lumens method), it calculates the illuminance at a specific point on a surface — for example, the light level on a desk, floor, or roadway.

Question 21

Zonal Cavity Method

Answer 21

A lighting design procedure used for predetermining the relation between the number and types of lamps or luminaires, the room characteristics, and the average illuminance on the work place. The zonal cavity method takes into account both direct and reflected flux.

Question 22

Light Loss Factor

Answer 22

A factor used in calculating illuminance after a given period and under given conditions (formerly called maintenance factor).

Question 23

Lamp Lumen Depreciation Factor

Answer 23

Multiplicative factor in calculations of illumination for reduction in the light output of a lamp over a period of time.

Question 24

Luminaire Dirt Depreciation Factor

Answer 24

Multiplicative factor used in calculations of illuminance for reduced illuminance due to dirt collecting on the luminaires.

Question 25

Recoverable Light Loss Equation

Question 26

Coefficient of Utilization

Answer 26

The ratio of the luminous flux (lumens) from a luminaire, calculated as received on the work plane, to the luminous flux emitted by the luminaire's lamps alone.

Question 27

Four steps in determining the Coefficient of Utilization

Answer 27

Step 1 Calculate the room cavity ratio Step 2 Select the basic reflectances of each surface Step 3 Determine the effective reflectances of each zone. Step 4 Determine the coefficient of utilization of this lighting system for the space or room using fixture manufacturer's published data.