Energy conservation extra MCQ
Electric lamp provides light when it reaches in the condition of incandescence in which the filament heat up after passing current.
thermocouple
incandescent
florescent
none is correct
Answer: b
Q2. Incandescent lamp is also known as incandescent light globe or bulb. True / False
Answer: True
Q3. Incandescent lamps are available in the voltage rating of ________.
10V – 100V
1.5V – 300V
1V – 200V
1V – 250V
Answer: b
Q4. The incandescent bulb has invented by Edison in 1879. True / False
Answer: True
The manufacturing cost of incandescent lamp is low. True / False
Answer: True
. The first commercial lamp was made with the material of ______ in 1879 by Edison.
carbonized power filament
metalized filament
osmium filament
tantalum filament
Answer: a
The best filament for incandescent lamp has ________ characteristics.
low temperature coefficient
high resistivity/melting point
mechanically strong
all are correct
Answer: d
Q10. The melting temperature of tungsten material is 3655°k. True / False
Answer: True
Q11. The most common type of filament used in the incandescent lamp is _______.
tantalum
carbon
tungsten
osmium
Answer: c
Q12. Nitrogen or Organ gasses are used inside gas-filled lamp. True / False
Answer: True
Q13. Why vacuum is created inside the bulb ?
decreases oxidation
convection
evaporation
a & b are correct
Answer: d
The best combination of inert gasses are Argon = 85% and Nitrogen = 15%. True / False
True
Why inert gasses are used inside bulb rather than vacuum ?
decreases evaporation
increase life of bulb
high efficiency
all are correct
Answer: d
The rating of bulb is described in __________.
volts
watts
ampere
a & b are correct
Answer: d
The incandescent lamp provides low light than fluorescent lamp. True / False
Answer: True
Incandescent bulbs can works on _______ supply.
AC
DC
a & b are correct
Answer: c
Q24. The power factor of incandescent lamp is high. True / False
Answer: True
Q25. Incandescent lamp will go burst when works during rain.
Answer: True
Magnesium vapour in a filament lamp gives
A. Green colour light...
B. Pink colour light
C. Blue colour light
D. White colour light
Filament lamps normally operate at a power factor of
A. Unity
B. 0.8 lagging
C. 0.5 lagging
D. 0.9 lagging
When a sodium vapour lamp is switched on initially the colour is
A. Red
B. Pink..
C. Yellow
D. Blue
The colour of light given out by a sodium vapour discharge lamp is
A. Pink
B. Bluish green
C. Yellow..
D. Blue
The ignition voltage for a sodium lamp is about
A. 100 to 150 v
B. 200 to 250 v
C. 300 to 400 v
D. 400 to 600 v..
Sodium vapour lamp needs and ionisation voltage of about
A. 5 v...
B. 20 v
C. 50 v
D. 100 v
E. 150 v
Which of the below emits nearly monochromatic light?
Mercury vapor lamp
Bulb
Tubelight
Sodium vapor lamp...
Applications:
Large areas like parks, street lighting, high ceiling buildings, and gyms
High-pressure mercury- vapour lamp emits:
Red colour light
Yellow colour light
White colour light
Bluish White colour light...
Which lamp has the best Colour Rendering Index (CRI)?
Fluorescent
Incandescent...
LED
High-pressure sodium vapor
Explanation
The most useful measure of a light source's color characteristics is the colour rendering index (CRI).
CRI is a measure of a light source's ability to show object colors "realistically" or "naturally" compared to a familiar reference source, either incandescent light or daylight.
The color rendering index (CRI) is measured as a number between 0 and 100.
At zero (0), all the colours look the same.
A CRI of 100 shows the true colors of the object.
Incandescent and halogen light sources have a CRI of 100.
The colour of light depends on
Options:
Wavelength
Frequency
Speed of light
Both (1) and (2)...
Which of the following is the most efficient lamp?
Options:
Graphene..
LED
CFL
Sodium vapour lamp
Solution
A graphene LED light bulb is simply an LED light bulb where the filament has been coated in graphene. A graphene LED bulb is reported to be 10% more efficient than regular LED light bulbs.
Important points
The luminous efficiency of the sodium vapour lamp is of the order of 45 to 50 lumens per watt.
The luminous efficacy of a typical CFL is 50–70 lumens per watt.
The luminous efficacy of a LED is around 90 lumens per watt.
For which of the following purposes are low voltage lamps used?
Options:
Flood lighting
Industrial lighting
Stadium lighting
Automotive lighting..
Candela is the unit of ________.
Options:
Luminous flux
Luminous effect
Luminous pressure
Luminous intensity...
Illumination is measured using which one of the following.
Options:
Millivolt meter
Stroboscope
Lux meter..
PH meter
The unit of illumination is:
Options:
Amperes
Lumens
Lux..
Candela
Solution
The unit of illumination is lux.
Candela is unit of luminous intensity.
Lumens is unit of luminous flux.
What is the initial operating voltage of a fluorescent lamp?
Options:
240 V
230 V
1100 V...
110 V
Explanation
Fluorescent starters are a timed switch and it provides ignition voltage to the fluorescent lamp.
The ignition voltage is as high as 1000 V to initiate a discharge in the argon gas lying between electrodes.
Ballast is used to limit the current in fluorescent tube.
The simplest sort of ballast, generally referred to as a magnetic ballast, works something like an inductor.
Steradian is the unit of
Options:
Planner angle
Solid angle...
Radiant efficiency
None of the above
The ratio of luminous flux emitted by a lamp to the power consumed by the lamp is ______.
Options:
Lux
Luminous Efficacy
Illuminance
CRI
Explanation
Luminous efficacy is a measure of how well a light source produces visible light.
It is the ratio of luminous flux to power, measured in lumens per watt in the International System of Units (SI).
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