SATHEE: Conservation Lawsfundamental Forcesestimation Of Distances Topic

Conservation Laws- Fundamental Forces- Estimation Of Distances

Conservation Laws

Conservation of energy: The total amount of energy in an isolated system remains constant, although it may change form.
Conservation of momentum: The total momentum of an isolated system remains constant, although it may be redistributed among different objects within the system.
Conservation of angular momentum: The total angular momentum of an isolated system remains constant, although it may be redistributed among different objects within the system.

Fundamental Forces

Gravitational force: Newton’s law of universal gravitation states that the force of gravity between two objects is inversely proportional to the square of the distance between them and directly proportional to the product of their masses.
Electromagnetic force: Coulomb’s law states that the electric force between two charged particles is inversely proportional to the square of the distance between them and directly proportional to the product of their charges.
Strong nuclear force: The strong nuclear force is the strongest of the four fundamental forces. It holds protons and neutrons together in the nucleus of an atom.
Weak nuclear force: The weak nuclear force is responsible for certain types of radioactive decay.

Estimation Of Distances

Parallax method: The parallax method is used to measure the distances to nearby stars. It involves observing the star from two different positions, such as the Earth and a spacecraft, and measuring the angle between the two lines of sight to the star.
Spectroscopic parallax: Spectroscopic parallax is used to measure the distances to more distant stars. It involves measuring the shift in the wavelength of light emitted by a star when it is observed from two different positions.
Cepheid variables: Cepheid variables are pulsating stars whose period of pulsation is related to their luminosity. By measuring the period of pulsation of a Cepheid variable, astronomers can estimate its luminosity, and then use that to estimate its distance.
Supernovae: Supernovae are extremely bright explosions of stars that can be used to measure distances to galaxies. By measuring the brightness of a supernova, astronomers can estimate its distance.

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