Author: John Mulindi
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The Bending of Starlight as Predicted by Einstein
Light falls in a gravitational field, for instance, a laser beam fired horizontally across a room will be closer to the ground on the side where it hits the far wall than it was when it left the laser. Likewise, a ray of light that is passing over a massive object like the sun will…
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The physics behind Global Positioning System (GPS)
The Global Positioning System (GPS) is a framework that allows anyone, with the aid of a small device, to identify exactly where they are on the earth’s surface. The GPS is made up of several satellites in accurate, well-known orbits around the earth. Each of these satellites contains a very accurate clock and a microwave…
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The Operation of Magnetically Levitated Trains (Maglevs)
Magnetic levitation (maglev), take place when the magnetic interaction is strong enough to balance the force of gravity. The like poles of two magnets repel one another, and if the magnets are placed vertically and the strength of the repulsion is the same as the strength of gravity, the net force is zero. The magnet…
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Newton’s Law of Universal Gravitation
Newton’s law of universal gravitation is a physical law that states that every particle attracts every other particle in the universe with the force of attraction directly proportional to the product of the masses and inversely proportional to the square of the distance between them. In other words, given any two objects A and B,…
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Basic Facts about Superconductors
Most of the conductors we use in our daily life are metals such copper wire. While these conductors are useful in many applications, they are not perfect as they have at least a small amount of resistance, which implies that some of the current is wasted. However with a special type of conductor (superconductor), this…
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Coulomb’s Law and Electric Field
According to Benjamin Franklin, we have two types of electric charges i.e. positive and negative charges. Positive and negative charges attract, but positive charges repel each other, as do negative charges. The force F that a pair of electric charges Q1 and Q2, separated by a distance r, exert on one another is given by…
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Uses of Static Electricity
Even though static electricity can be unsafe, it has some uses as discussed below: Electrostatic induction can also be applied to spread paint evenly on a surface. Tiny droplets of paint, when given the same charge, repel one another. When sprayed on a surface, such as the body of a car, the paint forms a…
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Newton’s Laws of Motions
Before Einstein, physicists believed that the behaviour of almost everything was controlled by three rules called “Newton’s Laws of Motion”. The basic point was to relate the motion of objects to the “forces” that act on that object. These forces picked out certain reference frames as special (Inertial frames). Newton’s First Law of Motion This…
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Basic Properties of Nuclei
All nuclei are made up of two types of particles, namely: protons and neutrons. The only exception is the ordinary hydrogen nucleus, which is a single proton. Atomic Number, Neutron Number, Mass Number and Isotopes The following quantities are used to describe the atomic nucleus: The symbol used to show how many protons and neutrons…
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Bohr’s Original Quantum Theory of Spectra
Regarded as one of the greatest discoveries, Niels Bohr’s original quantum theory of spectra was one of the most revolutionary and successful theory of atomic dynamics. Both Thomson and Rutherford recognized that the electrons must revolve about the nucleus in order to avoid falling into it. They along, with Bohr, realized that according to Maxwell’s…