PE ILLUMINATION

A standard candle emits a total luminous flux of lumens.

A standard candle emits a total luminous flux of lumens.

12.57

A lamp produces an illumination of 10 lux at a point 10m directly below it. What is its luminous intensity?

1000 Cd

An office building has a load density of 28 volt-amperes per square meter. If the total floor area of the building is 500 square meters, what is the total computed load?

14 KVA

A certain light source produces an illumination of 800 lux on surfaces. Find the illumination of 800 lux on surfaces. Find the illumination on that surfaces if the distance to the light is doubled

200 lux

A room 8m x 12m is lighted by 15 lamps to fairly uniform illumination of 100 lumens per sq meter. What is the coefficient of utilization if the output of each lamp is 1600 lumens?

40%

A road is illuminated by two 500 candela lamps placed 6.1 meters above the center line of the road and 18.3 meters apart. Find the illumination produced on the surface of the road at a point on the center line midway between lamps.

4.58 LUX

A room measuring 16m by 8m is to be illuminated by 8 lamps with an average illumination of 72 lm/sq.m at floor level. If 40% of the total light emitted is absorb by the walls and ceiling, calculate the mean spherical candle power required for each lamp.

153 Cd

The lighting load for a dwelling expressed in terms of a unit load in volt amperes per square meter must be at

24

A medium unshaded lamp hangs 8 m directly above the table. To what distance should it be lowered to increase the illumination to 2 times its former value?

5.66 m

Calculate the mean spherical candle power of a lamp emitting a flux of 1500 lumens

119.37 cd

A parking lot is to be illuminated by four floodlights placed on each corner of the lot mounted on 7 meters high poles. The parking lot measures 25 m x 20 m. If each lamp has an output of 500 candelas, calculate the illumination at the center of the lot.

25.72 lux

An office, 17 m x 8m wide is lighted by 8 lamps and each lamp has a luminous intensity of 200 Cd. Allowing an absorption loss of 4,000 Im for the reflectors, walls, and ceiling. Calculate the average illumination on the working plane.

118 lux

An area of 0.3 square meter is to be illuminated by a lamp at a level of 600 lux. What is the total luminous flux emitted by the lamp?

180 lm

What is the total flux emitted by a lamp having an intensity of 50 candelas?

628 lm

At what distance from a wall will 40 Cd lamp provide the same illumination as 80 Cd lamp located at 4 m from the wall?

2.83 m

A 100 candela lamp emits light uniformly in all directions and is suspended 2m above the center of a working table which is 3m square. Calculate the illumination at each corner of the table

8.08 lm/m^2

For indoor lawn tennis, what is the recommended level of illumination for tournaments in foot-candles (fc)?

50

A light source has an illumination of 100 footcandles (fc), what is the illumination in lux?

1075

What is the burning hours that should be used in the design consideration of incandescent bulb?

1500

A room with dimensions of 72 ft x 36 ft x 13 ft requires 50 footcandles, maintenance factor of 0.7 coefficients of utilization of 0.46 and RI of 4. Calculate the required lumens output of the lamps.

402,485

How far from a 150 Cd light source would a picture have to be placed so as to receive the same illumination as when it is placed 12m from an 85 Cd light source?

15.94 m

A light source located 2.75 m from a surface produces an illumination of 528 lux on the surface. Find the illumination if the distance is changed to 1.55 m

1662 lux

What is the total flux of light emitted from a source having a uniform intensity of 150 candlepower?

1885 lm

A floodlight emitting 25000 candelas in the center of its beam is aimed at 60 degrees to a point on the ground 20 meters away. The illumination of the point is

31.25

A lamp gives an output of 628 lm. What is its MSCP?

50

What is the total flux in lm emitted by a lamp having an intensity of 100 cd?

1256

The illumination in a drawing room having an area of 25 m^2 is 100 lux. Find the luminous intensity in candelas.

199

A uniform light source gives 2500 lm and is suspended 3.2 m above the center of a horizontal floor, 4m square. Find the illumination in lux at a point on the floor directly below the light source

19.43

A uniform light source gives 2500 lm and is suspended 3.2 m above the center of a horizontal floor, 4m square. Find the illumination in lux at each corner of the horizontal floor

8.18

A 150 cd lamp at a distance of 12.37 m give sufficient illumination on a certain working plane. How far in meters a 250 cd lamp be placed to have the same illumination on the working plane as before?

15.97

A lamp gives sufficient light to an object at a distance of 70 cm. By how much closer should the object be placed to double the illumination?

20.5 cm

The illumination on a certain object 2.5m from the light source is 6648 lux. Using the same light source, what is the illumination on the object in lux at 5m?

1662

A 540 cd lamp is 3m directly above a point A on the horizontal floor. If a plane mirror which reflects 75% of the light reaching it is placed horizontally 20 cm above the lamp, what will be the illumination at point A in lux?

95

A room with dimension of 72 ft by 36 ft by 13 ft requires an illumination of 60 foot-candles. MF = 0.7 and CU = 0.6. Calculate the required lumens output of the lamps.

370,286

A workshop, 20m by 12m requires an illumination of 150 lux on the working plane. If the efficiency of each lamp is 12 lm/watt and the supply is 230 V, 60 HZ, find the current required for the purpose in amperes. MF = 0.7 and CU = 0.45

41.4

A room, 8m by 12m is lighted by 15 lamps to a fairly uniform illumination of 100 lux. Calculate the coefficient of utilization given that each lamp emitted 1600 lm

0.4

A drawing room, 30m by 10m requires an illumination of 250 lux. The illumination is provided by 240 watt, luminaries having lamps of luminous intensity 14 lm/watt. MF = 0.9 and CU = 0.4. Find the number of luminaries required

62

A factory, 120m by 40m requires an illumination of 60 lux. Fluorescent luminaries each with 2 – 40 watt tubes are to be used. Each tube will emit 45 lm/watt. MF = 0.8 and CU = 0.5. How many luminaries are required?

200

At what distance from a wall will 4 cd lamp provide the same illumination as a 8 cd lamp located 4m from the wall?

2.83 m

An area of 3 m^2 is to be illuminated by a light source at a level of 550 lux. Find the luminous flux emitted by the light source in lm

1650

The MSCP of a lamp which gives out a total luminous flux of 400π lm is

100

Determine the average illumination of a room measuring 9.15 m by 12.2 m illuminated by a dozen 150 watt lamps. The luminous efficiency of each lamp is 14 lm/watt, MF = 1 and CU = 0.35

79

A factory space, 33m by 13m is to be illuminated by an average of 72 lux by 200 watt lamps. MF = 0.71 and CU = 0.4. The lumen output of 200 watt lamp is 2730 lm. Find the number of lamps required

40

How many lumens passed through an area of 0.8 m^2 on a sphere of radius 3m if a 650 cd isotropic source is at the center?

57.78

A group of 10 luminaries each with two 40 W cold-white fluorescent lamps are installed in a classroom. An appropriate CU of 0.65 is selected from the manufacturers chart, which also suggest an MF of 0.85. Determine the total lumens output of the luminaries if each lamp has an initial output of 2900 lumens.

32045 lumen

An unshaded lamp is 6m above the table. It is lowered down by 2m. By how much is the illumination on the table?

2.25 times

Four lamps are suspended 6m above the ground at the corners of a lawn 4m on each side. If each lamp emits 240 cd. Calculate the illumination at the center of the lawn?

20.56 lux

The study of illumination involves

design of lighting syste

Energy radiated continuously in the form of lighting waves is called

illumination

Luminous intensity is defined as

luminous flux / unit solid angle