## Prefixes

Prefixes are useful for expressing units of physical quantities that are either very big or very small. If you write out such big or small numbers, it will be time consuming and prone to errors. Some of the Greek prefixes and their symbols to indicate decimal sub-multiples and multiples of the SI units are: Number Prefix Number Prefix $10^{-9}$ nano …

## Base Quantity

A base quantity (or basic quantity) is chosen and arbitrarily defined, rather than being derived from a combination of other physical quantities. The 7 base quantities are: Physical quantity Base SI unit Mass (m) Kilogram (Kg) Length ($l$) Metre (m) Time (t) Second (s) Current ($\text{I}$) Ampere (A) Temperature (T) Kelvin (K) Amount of sub. (n) Molar (mol) Luminous Intensity …

## Physical Quantities

The study of Physics is based on experiments, which allowed us to test and validate theories. The results of those experiments are obtained by accurate measurements using physical quantities. All physical quantities consist of a numerical magnitude and a unit. The numerical magnitude denotes the size of the physical quantity. The unit denotes the physical quantity it is expressing. There are …

## Measurement Of Physical Properties

This topic covers “Measurement Of Physical Properties” of O Level Physics. (Equivalent to American high school diploma) If this is too basic for you, you can try the more advanced version here. Sub-Topics: Physical Quantities Base Quantities Prefixes Scalar and vector quantities Measurement Of Length Measurement Of Time Systematic Error & Random Error Parallax Error & Zero Error, Accuracy & …

## Interesting TED Talks

I will be placing TED talks that I find interesting in this post. Enjoy! NOTE: Sorry for the sizing of the videos. I’ll fix it soon. List: Astronomy – Sean Carroll: Distant time and the hint of a multiverse – Janna Levin: The sound the universe makes – Carter Emmart demos a 3D atlas of the universe Consumer Electronics – Mike Matas: …

## UY1: Calculation of moment of inertia of a thin spherical shell

Derivation of moment of inertia of a thin spherical shell A thin uniform spherical shell has a radius of R and mass M. Calculate its moment of inertia about any axis through its centre. Note: If you are lost at any point, please visit the beginner’s lesson (Calculation of moment of inertia of uniform rigid rod) or comment below. Initial ingredients Notice that …

## UY1: Thermal Bottleneck

If you consider that the first law says you cannot win (or you cannot get a free lunch), the second law says you cannot even break even (you cannot even eat all of your lunch): – The first law is essentially a statement of conservation of energy and says that you cannot get more energy (work) out of a heat …