Mcqs on Illumination | Electrical engineering

Mcqs on Illumination or multiple choice questions

1).The unit of luminous flux is...

a)    watt/m²

b)    lumen

c)    lumen/m²

d)    watt

Answer: b) 
Luminous flux is the quantity of the energy of the light emitted per second in all directions. The units of luminous flux is lumen. 

2).Due to moonlight ,illumination is nearly

a)    3000 lumens/m²

b)    300 lumens/m²

c)    30 lumens/m²   

d)    0.3 lumens/m²  

Answer: d) 

3). For precision work the illumination level required is of the order of

a)    500-1000 lumens/m²    

b)    200-400 lumens/m²

c)    50-100 lumens/m²

d)    10-25 lumens/m²

Answer: a)

4).For normal reading the illumination level required is around

a)    20-40 lumens/m²   

b)    60-100 lumens/m²

c)    200-300 lumens/m²

d)    400-500 lumens/m²

Answer: b)

5).Sometimes the wheels of rotating machinery under the influence of fluorescent lamps appear to be stationary. This is due to the

a)    low power factor  

b)    stroboscopic effect

c)    fluctuations

d)    luminescence effect

Answer: b)

6).The flicker effect of fluorescent lamps is more pronounced at

a)    lower frequencies

b)    Higher frequencies

c)    Lower voltage

d)    higher voltages

Answer: a)

7).Luminous flux is

a)    The light energy radiated by sun 

b)    The part of light energy,radiated by sun,which is received on the earth

c)    The rate of energy radiation in the form of light waves

d)    None of the above

Answer: c)

8). Which of the following is present inside the florescent tube?

a)    Argone and neon

b)    Argon and CO2

c)    Mercury vapour

d)    Helium and oxygen

Answer: c)

9).Due to Which of the following reasons the light of a tube appears cooler then that of a bulb?

a)    Tungsten is not used in the tube

b)    Tube is painted with milky colour

c)    Surface area of the tube is more then that of bulb   

d)    None of the above

Answer: a)

10). In fluorescent tubes ballast resistance is connected in series with the choke

a)    To reduce stroboscopic effects

b)    When tube operates on DC supply

c)    When supply frequency is low

d)    To reduce radio interference

Answer: c)