Exploring the Interstellar Medium, Stellar Evolution, and Galaxies
Chapter 15: Interstellar Medium
The interstellar medium, composed of gas and dust between stars, plays a crucial role in stellar evolution. Let’s delve into its key characteristics:
Composition and Density
- Primarily gas with a small fraction (1%) of dust.
- Extremely low density.
Interstellar Extinction and Reddening
- Solid dust grains (up to 300 nm) scatter and absorb light.
- Blue light is scattered more effectively, leading to the reddening of starlight.
Dust Grain Emission
- Dust grains absorb starlight and
Fluid Mechanics Fundamentals
NPSH and Cavitation
NPSHr (Net Positive Suction Head Required): Represents the minimum suction pressure needed to prevent cavitation under specific operating conditions.
NPSHa (Net Positive Suction Head Available): It represents the actual suction pressure available at the pump inlet. It is influenced by various factors, including:
- Elevation difference between the pump and the fluid level
- Presence of fittings and valves
- Compressibility of the fluid
It can be calculated or measured using pressure gauges
Read MoreDystopian Literature and Post-War Tension: A Comparative Analysis of Orwell, Yeats, and Auden
GEORGE ORWELL (1903-1950)
He was a journalist and essayist known for his clear and precise language, devoid of adornments. Born into an affluent family, Orwell was politically active throughout his life. After working as a police officer in Burma, he became deeply troubled by the political extremes of his time. Initially a convinced communist, his views shifted after witnessing the realities of the USSR. The 1940s marked a surge in political fiction, and Orwell contributed two seminal dystopian allegories:
Read MoreA Deep Dive into the Fundamentals of Physics: From Lasers to X-rays
Q. What is the working principle of a Laser? Write some applications of Laser.
A Laser (Light Amplification by Stimulated Emission of Radiation) operates based on three fundamental processes: stimulated emission, population inversion, and optical resonance.
Stimulated Emission: When an electron in an excited state of an atom or molecule drops to a lower energy state, it emits a photon (light particle). If this process is stimulated by an incident photon whose energy matches the energy difference
Galactic Central Discoveries and Cosmic Phenomena
Brightest star: Alpha Centauri. Retrograde motion: when Earth’s orbit crosses another planet such as Mars and then it seems as though the planet is going backward then forward again.
Galileo discovers: 4 moons of Jupiter, rings of Saturn, craters of the moon, and phases of Venus. 1st law of motion: objects change if force is applied. 2nd law: acceleration is caused by mass. 3rd law: for every reaction, equal opposite. Refracting telescope: chromatic aberration. Reflecting telescope: modern telescope,
Read MoreComprehensive Guide to English Language Exams (2019-2023)
English Language Exams (2019-2023)
Curso 2019-2020
OPCIÓN A: University Education
1)
- a) In the… TRUE: “It used to be that a university degree was a fast track to a good career.”
- b) There… TRUE: “Men studying English or philosophy may also earn less than the average man who left school at the age of 16.”
2)
- Because women earn lower salaries than men, and the jobs to which they have access if they don’t study are even lower.
- Yes, you can earn more money if you choose to study certain careers.