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
Liquid
Drop Model
It
was theory proposed by Niel Bohr in 1936, which treats the nucleons as if they
were molecules in a spherical drop of liquid. Scattering experiments with
various particles such as electrons, nucleons and α- particles reveal that to a
first approximation, nuclei can be considered spherical with essentially
constant density.
Lissajous
Figures
When a particle
is influenced simultaneously by two simple harmonic motions at right angles to
each other, the resultant motion of particle traces a curve called Lissajous
figure. Lissajous figures are helpful in determining ratio of time periods of
two vibrations.
Llyod’s
Mirror
Classic optical experiment in which the arrangement produces
interference pattern produced when part of the light from a slit falls directly
on a screen, and part is reflected from a mirror whose surface makes a small
angle with the incident beam.
Logarithm
The
exponent indicating the power to which a fixed number, the base, must be raised
to obtain a given number or variable.
If ax = M; then
logarithm of ‘M’ to base ‘a’ is ‘x’.
or
Logarithm
is defined as the exponent that indicates the power to which a number is raised
to produce a given number (i.e., the logarithm of 100 to the base 10 is 2).
London
Penetration Depth
It is the distance inside the surface of
superconductor at which flux density falls to 1/e of its value at the surface.
Long
Range Alpha Particles
If the parent
alpha emitter emits alpha particles when it is in an excited state then we get
long range alpha particles.
Longitudinal
Strain
It is the change
in length per unit original length or it is fractional change in length.
Longitudinal Stress
When a force is
applied on a body such that there is a change in the length of the body, the
longitudinal force per unit area is called longitudinal stress.
Longitudinal
Wave Motion
Wave
motion in which particles of medium vibrate along the direction of propagation
of wave.
Longitudinal
Wave
Wave motion in
which particles of medium vibrate along direction of propagation of wave.
Lorentz
Fitzerald Contraction
The length of
moving rod is contracted along the direction of motion by a factor sqrt[1-(v2/c2)]
while there is no contraction along a direction perpendicular to the direction
of motion.
Lorentz
Force
The force which
acts on an electric charge when placed in magnetic field is called as Lorentz
force. The total force on a charge ‘q’ moving with velocity ‘V’ in an electric
field ‘E’ and magnetic field ‘B’ is F = q(E+VxB). Magnetic
Lorentz force is perpendicularly to both velocity ‘V’ and the magnetic fiekld
‘B’. Hence it does no work for a steady magnetic field.
Lorentz-Fitzerald
Contraction
Every rigid body appears to have maximum dimensions when at rest relative to the observer. Its dimension appear to be contracted in the direction of relative motion by factor sqrt(1 - V2/C2) when it moves with velocity ‘V’ relative to observer.
Loschmidt’s
Number
The no. of
molecules per unit volume of an ideal gas at 0 oc and normal atmospheric pressure. The number is
2.68719±0.0001 x 1019 cm-3.
Loud
Speaker
Device used to
convert electrical energy usually generated by microphone into sound energy.
The loud speaker consists of a diaphragm and an electromagnet. When the
changing current flows through the coil of an electromagnet, the magnetic flux also
changes. Due to change in magnetic flux, the diaphragm is set into vibration.
Hence electrical energy is converted into sound.
Loudness
of Sound
The
amount of sound energy crossing per unit area around a point in one second is
known as intensity of sound.
Loudness
α log (intensity); ‘L’ represents sensation of loudness; ‘I’ represents
intensity of sound
LS Coupling
It is also called Russell – Saunders scheme. This is the coupling of total orbital angular momentum L with total spin angular momentum S, to give a total momentum J. This coupling first involves independent coupling of individual electronic orbital angular momentum to give a total resultant orbital angular momentum (L) and the independent coupling of individual spin angular momentum to give resultant total spin momentum ‘S’.
It is the amount of light energy emitted per second by a uniform (point) source of one candela with in a cone of unit solid angle.
The property of emission of light by solids due to electron transitions is called as Luminescence. The phenomenon exhibited by some semiconductors, particularly compound semiconductors with direct band gaps in which electrons (carriers) are excited into higher impurity levels from which they fall into equilibrium states, giving off light.
The comparative degree to which light of a given wavelength induces sensation of brightness when perceived.
or
The relative quantity of radiation emitted by celestial source such as star.
Total visible energy emitted by a source per unit time is called as total luminous flux from the source.
Time taken by the earth to complete one revolution round the sun.
SI unit of illuminance, equal to one lumen /m2.
The spectrum of wavelength falling in Ultraviolet region of electromagnetic spectrum due to transition of electrons from higher energy states (orbits) to first orbit (inner most orbit) is called Lyman series.
