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Index (L)
LA - LC
LD - LF
LG - LJ
LK - LN
LO - LR
LS - LV
LW - LZ
Moment of truth
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More than 25 million people died in Europe from the bubonic plague (the black death) in five years, from 1347 to 1352. |
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A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
LS - LV
lumen Metro.
A latin word for light, lumen is the SI unit (abbreviation: lm) for measuring the luminous flux produced by a light source equal to the intensity of
1 candela (Cd) in a solid angle of 1 steradian. In other words, it is the amount of light which falls on unit area of surface at a unit distance from
a source of 1 Cd.
luminosity Phys.
The visual perception of the brightness of an object, or the density of luminous intensity in a particular direction.
luminosity class Astron.
The total energy (including light) radiated by a star at all wavelengths, in a second. It is one of the basic properties for star characterization. A luminosity classification scheme is used to compare the brightness of stars
with the same temperature or spectral class.
Luminosity class |
Star type |
Ia |
largest supergiants |
Ib |
supergiants |
II |
bright giants |
III |
giants |
IV |
subgiants |
V |
dwarfs |
VI |
subdwarfs |
wd |
white dwarfs |
Luminosity class V stars are also known as main-sequence stars because most of the stars fall on this category. A star's luminosity is roughly equal to the cube of a star's mass.
lux Metro.
The SI unit, symbol lx, of measuring illuminance which is equal to the illumination produced by a luminous flux of 1 lumen distributed uniformly over an area of 1 square meter (1 lx = 1 lm/m2).
LS - LV
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
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