Physics Talk

Credit - ParallelVision: https://pixabay.com/illustrations/black-hole-nebula-space-eye-5868615/ Black holes are usually defined as regions of space-time that are so dense that nothing, not even light can escape from it. However, this is not quite true. It turns out that black holes could be evaporating, losing mass, and shrinking in the process. This phenomenon, proposed by Stephen Hawking in 1974, is called Hawking radiation.   “Black holes ain’t as black as they are painted” – Stephen Hawking, August 2015   In empty space, pair production and annihilation occur spontaneously. Pair production describes the formation of a particle and its corresponding antiparticle, normally from the interaction of a high energy photon with a heavier particle. For example, an electron and a positron (antiparticle of the electron) can be formed when a high energy photon interacts with an atomic nucleus. Pair annihilation is essentially the reverse of this process: a particle colliding with its

Credit - JohnsonMartin: https://pixabay.com/illustrations/wormhole-space-time-light-tunnel-739872/ Wave-particle duality is a key aspect of quantum mechanics. The wave characteristics of a particle are mathematically described by a quantity called the wave function. The square of the modulus (absolute value) of the wave function at a given position represents the probability of finding the particle at that point. 1 Quantum mechanics is inherently probabilistic. It is only when an observation is made that the wave function collapses. This feature is most apparent in the double-slit experiment which was talked about in the previous post ( https://phys-talk.blogspot.com/2020/09/the-problem-with-quantum-mechanics.html ). The wave-like nature of particles paves the way for an interesting phenomenon known as quantum tunnelling. Going through walls Quantum tunnelling is the phenomenon of particles passing through ‘seemingly impassable force barriers.’ 2 Consider a ball rolling up a hill

  Credit - geralt: https://pixabay.com/illustrations/physics-quantum-physics-particles-3871216/ Quantum mechanics is currently seen as ‘the best description we have of the nature of the particles that make up matter and the forces with which they interact.’ [1] The key ideas of quantum physics include wave-particle duality and quantised properties. Wave-particle duality is the concept that all physical entities behave as both waves and particles simultaneously. For instance, electrons undergo diffraction which is a wave effect. Meanwhile, radiation is emitted in small discrete packets or quanta called photons. These photons can be considered as particles. Each photon contains an amount of energy. Therefore, light energy is quantised. Quantum mechanics has been incredibly successful since its development in the early 20 th century. Most notably, they underpin the science behind transistors, fundamental to modern electronics, which are composed of semiconductors: the energy bands in se

Guillom assumed (based on copyright claims): https://commons.wikimedia.org/wiki/File:N-doped_Si.svg In Part 1 ( https://phys-talk.blogspot.com/2020/07/semiconductors-part-1-introduction-band.html ), we looked at the basics of semiconductors, using band theory to visualise how they differ from insulators and conductors. From Part 1, we learned that silicon is classed as a semiconductor due to the small energy gap between the valence and conduction bands. However, the conductivity of pure silicon is low and therefore it is not very useful in electronics. Doping is a method implemented to alter the properties of a semiconductor and modify its conductivity. It involves adding impurities to an intrinsic semiconductor (like silicon) to ‘generate either a surplus or a deficiency in valence electrons.’ [1] This imbalance allows for the movement of electrons through the material and therefore current can flow. N-type semiconductors This diagram shows the structure of doped Silicon: Phosp