the arrival of the last prelim paper

tmr's physics mcq, last paper for prelims. finally, can liberate myself from studying and PLAY. hahha.

45 more days to a levels after the paper tomorrow. well, one step towards the end of the prelims brings us one step closer to A levels.

anyway, i was doing some physics paper, then wanted to clarify some concepts. so went online to check.

here they are:

Population inversion
More atoms in the higher energy level than the lower energy levels.

Rankine scale
It starts at 0R at -273°C, like the Kelvin scale. However, one unit of Rankine corresponds to that of one unit of Fahrenheit, unlike one unit on the Kelvin scale which corresponds to one unit of degree Celsius.

Laser pumping
A mean of transferring energy to a system for it to gain energy, which can help the system obtain population inversion

Optical pumping
This is a subset of laser pumping, which transfer light energy to the system.

Heisenberg uncertainty principle
In locating a unit of matter, it is uncertain to a inversely proportionate uncertainty in the momentum provided, due to inaccuracy in measurement, vice versa. This uncertainty is irregardless of experimental set-up, and the proportionality constant is /2.

Carbon dioxide laser
This is one of the first form of laser to be discovered, and is still one of the most useful due to its high power and efficiency. Basically, this is just another form of laser. (The common one we hear about is the He-Ne Laser.)

Maser
Laser is a subset of this, even though the acronym suggest that it only produce the microwave wavelength of the electromagnetic spectrum, which is not true.

click here to see a picture of a hydrogen maser *It's really cool

Hydrogen Maser
A form of MASER

Rømer scale / Réaumur scale

Just other temperature scales.

Gravitional Redshift
Basically, this means that even electromagnetic radiation, e.g. light, will gain and lose energy when they move in a gravitational field. It's like how you would expect masses to change in kinetic energy(KE) when you allow them to fall freely. Electromagnetic radiation have higher energy in a lower gravitational field compared to that in a higher gravitational field. Likewise, you would expect masses to have higher KE after they have moved from a region of higher gravitational field to smaller gravitational field. (Gravitational potential energy is converted to kinetic energy in the case of the mass.)

well, maybe if you are doubtful about whether your concepts are exactly right, go check them out. don't bother with the equations though, unless you wanna take physics to uni. guess it's not required for us to know their equations at our level of education.

Interesting reads
-LASER is the acronym of Light Amplification by Stimulated Emission of Radiation.
-When hydrogen maser is used as a clock, it will have an uncertainty of 1 second every 63million years
-an atom with electrons in the same spin have more energy than one with opposite spins.

*I'm wondering what's a ruby maser though, could not gather much information about it.