  ### 1.Which of the following statements is correct?

• ALight is a form of heat energy
• BLight is a form of electrical energy
• CLight consists of shooting particles
• DLight consists of electromagnetic waves

Light consists of electromagnetic waves

Explanation:

### 2.Luminous efficiency of a fluorescent tube is

• A10 lumen/watt
• B20 lumen/watt
• C40 lumen/watt
• D60 lumen/watt

60 lumen/watt

Explanation:

Luminous efficiency of a fluorescent tube is 60 lumen/watt. Luminous efficiency is the ratio of luminous flux output to input power. Its unit is Lumen/Watt.

### 3.Candela is the unit of which of the following?

• AWavelength
• BLuminous intensity
• CLuminous flux
• DFrequency

Luminous intensity

Explanation:

Candela is the unit of Luminous intensity.  Luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle. The SI unit of luminous intensity is Luminous flux per unit solid angle or Lumen per Steradian or Candela.

### 4.Colour of light depends upon

• AFrequency
• BWave length
• CBoth (a) and (b)
• DSpeed of light

Both (a) and (b)

Explanation:

### 5.Illumination of one lumen per sq. meter is called  ____________

• ALumen meter
• BLux
• CFoot candle
• DCandela

Lux

Explanation:

Illumination of one lumen per sq. meter is called Lux. One lux is equal to one lumen per square metre.

### 6.A solid angle is expressed in terms of  ____________

• DDegrees

Explanation:

A solid angle is expressed in terms of Steradians.

### 7.The unit of luminous flux is  ___________

• AWatt/sq. Metre
• BLumen
• CLumen/sq. Metre
• DWatt

Lumen

Explanation:

The unit of luminous flux is Lumen.

### 8.Incandescent lamps (Filament lamps) operate normally at a power factor of

• A0.5 lagging
• B0.8 lagging
• CUnity

Unity

Explanation:

Incandescent lamps (Filament lamps) operate normally at a power factor of Unity.

### 9.The filament of a GLS lamp is made of

• ATungsten
• BCopper
• CCarbon
• DAluminium

Tungsten

Explanation:

The filament of a GLS lamp is made of Tungsten.

### 10.Fine diameter tungsten wires are made by

• ATurning
• BSwaging
• CCompressing
• DWire drawing

Wire drawing

Explanation:

Fine diameter tungsten wires are made by Wire drawing.

### 11.What percentage of the input energy is radiated by filament lamps?

• A2 to 5 percent
• B10 to 15 percent
• C25 to 30 percent
• D40 to 50 percent

10 to 15 percent

Explanation:

10 to 15 percent of the input energy is radiated by filament lamps.

### 12.Which of the following lamps is the cheapest for the same wattage?

• AFluorescent tube
• BMercury vapour lamp
• CGLS lamp
• DSodium vapour lamp

GLS lamp

Explanation:

GLS  lamps is the cheapest for the same wattage.

• A100 W
• B75 W
• C40 W
• D15 W

75 W

Explanation:

### 14.In house the illumination is in the range of

• A2 ? 5 lumens/watt
• B10 ? 20 lumens/watt
• C35 ? 45 lumens/watt
• D60 ? 65 lumens/watt

60 ? 65 lumens/watt

Explanation:

### 15.?The illumination is directly proportional to the cosine of the angle made by the normal to the illuminated surface with the direction of the incident flux?. Above statement is associated with

• ALambert?s cosine law
• BPlanck?s law
• CBunsen?s law of the illumination
• DMacbeth?s law of illumination

Lambert?s cosine law

Explanation:

### 16.The colour of sodium vapour discharge lamp is

• ARed
• BPink
• CYellow
• DBluish green

Yellow

Explanation:

The colour of sodium vapour discharge lamp is Yellow.

### 17.Carbon Arc lamps are commonly used in

• APhotography
• BCinema projectors
• CDomestic lighting
• DStreet lighting

Cinema projectors

Explanation:

Carbon Arc lamps are commonly used in Cinema projectors.

### 18.Desired illumination level on the working plane depends upon

• AAge group observers and Whether the object is stationary or moving
• BSize of the object to be seen and its distance from the observer
• CWhether the object is to be seen for longer duration or shorter duration of time
• DAll above factors

All above factors

Explanation:

### 19.On which of the following factors does the depreciation or maintenance factor depend?

• ALamp cleaning schedule
• BAgeing of the lamp
• CType of work carried out at the premises
• DAll of the above factors

All of the above factors

Explanation:

### 20.In lighting installation using filament lamps  1% voltage drop results into

• ANo loss of light
• B1.5 percent loss in the light output
• C3.5 percent loss in the light output
• D15 percent loss in the light output