Q. 1.Explain gravitational waves.
Words limit = 150+ words!
Q. 2. Exaplin the factors affecting the value of 'g'.
Explain with full details!
Answers
ANSWER:
GRAVITATIONAL WAVES!
Waves are created on the surface of water when we drop a stone into it. Similarly you must have seen the waves generated on a string when both its ends are held in hand and it is shaken. Light is also a type of wave called the Electromagnetic wave.
Gamma rays, X-rays, ultraviolet rays, infrared rays, microwave and radio waves are all different types of electromagnetic waves. Astronomical objects emit these waves and we receive them using our instruments. All our knowledge about the universe has been obtained through these waves.
Gravitational waves are a very different type of waves. They have been called the waves on the fabric of space-time. Einstein predicted their existence in 1916. These waves are very weak and it is very difficult to detect them. Scientists have constructed extremely sensitive instruments to detect the gravitational waves emitted by astronomical sources. Among these LIGO (Laser Interferometric G
Gravitational wave Observatory) is the prominent one. Exactly after hundreds years of their prediction, scientists detected these waves coming from an astronomical source.Indian scientists have contributed significantly in this discovery. This discovery has opened a new path to obtain information about the Universe.
ANS. 2
The value of the acceleration due to gravity, g, changes from place to place on the earth. It also varies with the altitude and depth below the earth's surface. The factors affecting the value of g are the shape of earth, altitude and depth below the earth's surface.
The earth is not perfectly spherical. It is somewhat flat at the poles and bulging at the equator. At the surface of the earth, the value of g is maximum (9.832 m/s^2) at the poles as the polar radius is minimum ,while it is minimum (9.78 m/s^2) at the equator as the equatorial radius is maximum.
As the height (h) above the earth's surface increases, the value of g decreases.
It varies as 1/(R+h)^2,
where R is radius of earth.
In the interior of the earth, on the average, the value of g is less than that at the earth's surface. The depth below the earth's surface increases and the value of g decreases and finally it becomes zero at the centre of the earth.
Answer:
IT IS NOT COPIED FROM NASA WEBSITE
Explanation:
Gravitational waves are 'ripples' in space-time caused by some of the most violent and energetic processes in the Universe. Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity. Einstein's mathematics showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that 'waves' of distorted space would radiate from the source (like the movement of waves away from a stone thrown into a pond). Furthermore, these ripples would travel at the speed of light through the Universe, carrying with them information about their cataclysmic origins, as well as clues to the nature of gravity itself.
The strongest gravitational waves are produced by catastrophic events such as colliding black holes, the collapse of stellar cores (supernovae), coalescing neutron stars or white dwarf stars, the slightly wobbly rotation of neutron stars that are not perfect spheres, and possibly even the remnants of gravitational radiation created by the birth of the Universe.
Factors affecting acceleration due to gravity (g):
1. As the height (altitude) increases acceleration due to gravity (g) decreases
2. As the depth increases acceleration due to gravity (g) decreases
3. Local conditions affect the acceleration due to gravity (g) slightly by the geological deposits, massive concrete buildings and topography
4. At the poles acceleration due to gravity (g) is maximum
5. At the equator acceleration due to gravity (g) is minimum