Recent Trends In Physics All Notes
Higgs field is a field that gives mass to elementary particles when these particles interact with it.
The particle associated with Higgs field is called Higgs Boson.
Higgs Boson is an elementary particle produced by quantum excitation of Higgs field.
It is named after physicists Peter Higgs.
When particles interact with Higgs field and attract Higgs Boson, it will cluster around the particles in varying number.
The more particle attract Higgs Boson, more will be its mass.
This is called god particles because it was very difficult to detect the particle. it took almost 50 years and billion dollar particle
accelerator to perform it. This nickname was used by Leon Lederman for first time.
Gravitational waves
Gravitational waves are 'ripple' in space time which is caused by some of the most violent and energetic processes in the universe.
These processes may include massive accelerating objects such as neutrons or black hole orbiting each other.
These processes would disrupt space time in such a way that 'waves' of space-time would propagate in all direction away from the source.
These waves travel at speed of light carrying into about their origin.
In 1916 AD, Albert Einstein suggested about existence of gravitational waves in his general theory of relativity.
Later in 2015, LIGO [Laser Interferometer Gravitational Wave Observatory] detected gravitational waves produced by a pair of colliding black hole (36 and 29 times larger than sun) about 1.3 billion light years away. This proved Einstein's prediction.
Nanotechnology
It is manipulation of matter on atomic, molecular and supra molecular scale.
It involves control of matter from 1-100 nm.
It has potential to create many new materials and devices with vast range of application such as in medicine, electronics and energy production.
Nanoparticles used in field of food science and food microbiology.
Seismology
Seismology is the scientific study of earthquake and seismic waves that moves through and around the earth or through other planets like bodies.
Seismic waves:
They are elastic waves which can propagate in solid or fluid materials. They are categorized into two types:
1. Body waves:
Body waves are those waves which travel through interior of materials. They are sub categorized into two types:
a. P-waves (Pressure / Primary):
They are longitudinal waves which involves compression and expansion in the direction of propagation.
Fastest kind of seismic waves.
It can travel through solids and liquids.
They push and pull the rock as they move through.
b) S-waves (Shear / Secondary):
It is second wave we feel on earthquake.
It is slower than P-wave.
It can travel only through solid.
It moves rock particles up and down to direction perpendicular to direction of propagation.
2. Surface waves:
Surface waves are those waves which travel along surface or interfaces of matter. They are result of S-waves and P-waves. Further, they are classified into two types:
a. Love wave:
Named after A.E.H Love.
It is formed by horizontally polarized S-waves interacting with surface.
It only exists if there is change in elastic properties with depth in solid medium.
b. Rayleigh waves:
Named after Lord Rayleigh.
It has both compressional and shear motions.
It results from interaction of P-waves and vertically polarized S-waves with surface.
It can exist in any solid medium.
It rolls along the ground just like a wave rolls across a lake or an ocean.
It moves the ground up and down and side to slide in same direction.
Most of the shaking from an earthquake is due to Rayleigh wave.
Origin of earthquake
Fault is a zone of fracture between two block of rock.
This fault can be natural or created by volcanic eruption, bomb blasts, etc.
When rock underground suddenly slide along a fault. They stick a little and don't just slide smoothly.
After a while, rock breaks and energy releases.
This sudden release of energy cause the seismic waves that make the ground shake.
The rock continues to move until they get stuck again. The spot of origination of seismic wave is called hypocenter or focus.
The place right above the focus is called epicenter of earthquake.
Gorkha Earthquake - 2015 (2072)
Magnitude - 7.8
Epicenter - Gorkha district at Barpak.
Time - 11:56 AM on 25 April 2015 (12 Baisakh 2072)
Hypocentre - 8.2 km deep.
After shock = 12 May 2015 at 12:50, 7.3
