MOCK
Q.402- FRAMED FROM "The Hindu"
Q.
With reference to the Halogen Light Bulbs, consider the following statements :
1.
White coating also known as Phosphor coating on the glass absorbs UV light
& protect from the UV rays
2.
They have the same tungsten filament as the typical incandescent light bulbs
3.
Fluorescent coating is often used in these bulbs to add brightness
Select
the correct answer using the codes given below :
A)
2 & 3
B)
1,2,3
C)
Only 2
D)
1 & 2
Ans.
C
Fluorescent
bulbs : White coating also known as Phosphor coating on the glass absorbs UV
light & protect from the UV rays
Vapour
lamps : Fluorescent coating is often used in these bulbs to add brightness
A
halogen lamp, also known as a tungsten halogen, quartz-halogen or quartz iodine
lamp, is an
incandescent
lamp consisting of a tungsten filament sealed into a compact transparent
envelope that is
filled
with a mixture of an inert gas and a small amount of a halogensuch as iodine or
bromine.
The
combination of the halogen gas and the tungsten filament produces a halogen
cycle chemical reaction
which
redeposits evaporated tungsten to the filament, increasing its life and
maintaining the clarity
of
the envelope. For this to happen, a halogen lamp must be operated at a higher
envelope temperature
(250°
C; 482° F)[1] than a standard vacuum incandescent lamp of similar power and
operating life; this
also
produces light with higher luminous efficacy and color temperature. The small
size of halogen
lamps
permits their use in compact optical systems for projectors and illumination.
The small glass
envelope
may be enclosed in a much larger outer glass bulb for a bigger package; the
outer jacket will
be
at a much lower and safer temperature, and it also protects the hot bulb from
harmful contamination
and
makes the bulb mechanically more similar to a conventional lamp that it might
replace.
Standard
and halogen incandescent bulbs are much less efficient than LED and compact
fluorescent lamps,
and
have been banned in many jurisdictions because of this.
