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Metric prefixes for powers of 10 and their symbols
Prefix Symbol Value See Appendix A for a discussion of powers of 10. Example (some are approximate)
exa E 10 18 size 12{"10" rSup { size 8{"18"} } } {} exameter Em 10 18  m size 12{"10" rSup { size 8{"18"} } " m"} {} distance light travels in a century
peta P 10 15 size 12{"10" rSup { size 8{"15"} } } {} petasecond Ps 10 15  s size 12{"10" rSup { size 8{"15"} } " s"} {} 30 million years
tera T 10 12 size 12{"10" rSup { size 8{"12"} } } {} terawatt TW 10 12  W size 12{"10" rSup { size 8{"12"} } `W} {} powerful laser output
giga G 10 9 size 12{"10" rSup { size 8{9} } } {} gigahertz GHz 10 9  Hz size 12{"10" rSup { size 8{9} } `"Hz"} {} a microwave frequency
mega M 10 6 size 12{"10" rSup { size 8{6} } } {} megacurie MCi 10 6  Ci size 12{"10" rSup { size 8{6} } `"Ci"} {} high radioactivity
kilo k 10 3 size 12{"10" rSup { size 8{3} } } {} kilometer km 10 3  m size 12{"10" rSup { size 8{3} } " m"} {} about 6/10 mile
hecto h 10 2 size 12{"10" rSup { size 8{2} } } {} hectoliter hL 10 2  L size 12{"10" rSup { size 8{2} } " L"} {} 26 gallons
deka da 10 1 size 12{"10" rSup { size 8{1} } } {} dekagram dag 10 1  g size 12{"10" rSup { size 8{1} } `g} {} teaspoon of butter
10 0 size 12{"10" rSup { size 8{0} } } {} (=1)
deci d 10 1 size 12{"10" rSup { size 8{ - 1} } } {} deciliter dL 10 1  L size 12{"10" rSup { size 8{ - 1} } `L} {} less than half a soda
centi c 10 2 size 12{"10" rSup { size 8{ - 2} } } {} centimeter cm 10 2  m size 12{"10" rSup { size 8{ - 2} } `m} {} fingertip thickness
milli m 10 3 size 12{"10" rSup { size 8{ - 3} } } {} millimeter mm 10 3  m size 12{"10" rSup { size 8{ - 3} } `m} {} flea at its shoulders
micro µ 10 6 size 12{"10" rSup { size 8{ - 6} } } {} micrometer µm 10 6  m size 12{"10" rSup { size 8{ - 6} } `m} {} detail in microscope
nano n 10 9 size 12{"10" rSup { size 8{ - 9} } } {} nanogram ng 10 9  g size 12{"10" rSup { size 8{ - 9} } `g} {} small speck of dust
pico p 10 12 size 12{"10" rSup { size 8{ - "12"} } } {} picofarad pF 10 12  F size 12{"10" rSup { size 8{ - "12"} } F} {} small capacitor in radio
femto f 10 15 size 12{"10" rSup { size 8{ - "15"} } } {} femtometer fm 10 15  m size 12{"10" rSup { size 8{ - "15"} } `m} {} size of a proton
atto a 10 18 size 12{"10" rSup { size 8{ - "18"} } } {} attosecond as 10 18  s size 12{"10" rSup { size 8{ - "18"} } `s} {} time light crosses an atom

Known ranges of length, mass, and time

The vastness of the universe and the breadth over which physics applies are illustrated by the wide range of examples of known lengths, masses, and times in [link] . Examination of this table will give you some feeling for the range of possible topics and numerical values. (See [link] and [link] .)

A magnified image of tiny phytoplankton swimming among the crystal of ice.[
Tiny phytoplankton swims among crystals of ice in the Antarctic Sea. They range from a few micrometers to as much as 2 millimeters in length. (credit: Prof. Gordon T. Taylor, Stony Brook University; NOAA Corps Collections)
A view of Abell Galaxy with some bright stars and some hot gases.
Galaxies collide 2.4 billion light years away from Earth. The tremendous range of observable phenomena in nature challenges the imagination. (credit: NASA/CXC/UVic./A. Mahdavi et al. Optical/lensing: CFHT/UVic./H. Hoekstra et al.)

Unit conversion and dimensional analysis

It is often necessary to convert from one type of unit to another. For example, if you are reading a European cookbook, some quantities may be expressed in units of liters and you need to convert them to cups. Or, perhaps you are reading walking directions from one location to another and you are interested in how many miles you will be walking. In this case, you will need to convert units of feet to miles.

Let us consider a simple example of how to convert units. Let us say that we want to convert 80 meters (m) to kilometers (km).

The first thing to do is to list the units that you have and the units that you want to convert to. In this case, we have units in meters and we want to convert to kilometers .

Next, we need to determine a conversion factor    relating meters to kilometers. A conversion factor is a ratio expressing how many of one unit are equal to another unit. For example, there are 12 inches in 1 foot, 100 centimeters in 1 meter, 60 seconds in 1 minute, and so on. In this case, we know that there are 1,000 meters in 1 kilometer.

Now we can set up our unit conversion. We will write the units that we have and then multiply them by the conversion factor so that the units cancel out, as shown:

80 m × 1 km 1000 m = 0 .080 km. size 12{"80"" m" times { {"1 km"} over {"1000 m"} } =0 "." "080"`"km"} {}

Note that the unwanted m unit cancels, leaving only the desired km unit. You can use this method to convert between any types of unit.

Questions & Answers

what is physics
Chiwetalu Reply
branch of science which deals with matter energy and their relationship between them
Life science
what is heat and temperature
Kazeem Reply
how does sound affect temperature
Clement Reply
sound is directly proportional to the temperature.
how to solve wave question
Wisdom Reply
I would like to know how I am not at all smart when it comes to math. please explain so I can understand. sincerly
Just know d relationship btw 1)wave length 2)frequency and velocity
First of all, you are smart and you will get it👍🏽... v = f × wavelength see my youtube channel: "mathwithmrv" if you want to know how to rearrange equations using the balance method
nice self promotion though xD
thanks dear
hi pls help me with this question A ball is projected vertically upwards from the top of a tower 60m high with a velocity of 30ms1.what is the maximum height above the ground level?how long does it take to reach the ground level?
please guys help, what is the difference between concave lens and convex lens
Vincent Reply
convex lens brings rays of light to a focus while concave diverges rays of light
for mmHg to kPa yes
it depends on the size
Matthew Reply
please what is concave lens
a lens which diverge the ray of light
concave diverges light
thank you guys
A diverging lens
What is isotope
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element. "some elements have only one stable isotope
what is wire wound resistors?
Naveedkhan Reply
What are the best colleges to go to for physics
Matthew Reply
I would like to know this too
How do I calculate uncertainty in a frequency?
Rebecca Reply
Calculate . ..
What is light wave
Sakeenah Reply
What is wave
What is light
explain how neurons communicate feed and stimulate
Great science students
A wave is a disturbance which travels through the medium transferring energy from one form to another without causing any permanent displacement of d medium itself
Light is a form o wave
Neurons communicate by sending message through nerves in coordination
What are petrochemicals, give two examples
light has dual nature, particle as well as wave. when we want to explain phenomena like Interference of light, then we consider light as wave.
what is it as in the form of it or how to visualize it or what it contains
particles of light are like small packets of energy called photons, and flow or motion of photons is wave like
light is just the energy of which photons emit
the wave is how they travel
photons do not emitt energy, they are energy. They are massless particles.
a wave is a disturbance through the medium. Have you ever thrown a stone in still water? the disturbance produced travels in form of wave, the wave produced by throwing stone in still water are circular in nature.
a photon does contain mass when in motion. it doesnt contain mass when at rest
when would it ever be at rest
a wave is a disturbance of which energy travels
that's darkness. darkness has no mass because the photons within in aren't moving or producing energy
Hi guys. Please I've been trying to understand the concept of SHM, but it's not been really easy, could someone please explain it to me or suggest a site I could visit? Thank you.
effective mass of photons only comes into picture when we consider it accelerating in gravitational field, mass of photon has no meaning as it is always travelling with speed of light and is never at rest. with that high speed, Energy and momentum are equivalent. and darkness is absense of photons.
darkness is absense of light. not the presence of 'resting photons'. photons are never at rest.
photons are present in darkness but don't give off any light because they are stationary with no mass or energy. once a force makes them move again they will gain mass and give off light
this theory is presented in Einsteins theory of special relativity
A.The velocity Vo for the streamline flow of liquid in a small tube depends on the radius r of the tube,the density and the viscosity iter of the liquid .use the dimensional analysis to obtain an expression for the velocity . B.Given that Vo =r square ×p all over 4×iter ×l
A.The velocity Vo for the streamline flow of liquid in a small tube depends on the radius r of the tube,the density (rho)and the viscosity (iter)of the liquid. Use the method of dimensional analysis to obtain an expression for the velocity . B.Given that Vo =r square x p all over 4 x iter x l
Matthew, photons ARE light. there is no such thing as a photon that isn't moving. in fact the speed they move at is called C (for constant) in physics. through a vacuum they always travel at this speed no matter what. they can not slow down; except in another medium.
The reason why a photon can go at this speed is BECAUSE it had no mass. nothing can go this speed or faster because it needs to have no mass or negative mass. that's why it's called the constant.
when a photon hits something that is opaque, this is the only way to "stop"it. it isn't merely stopped but absorbed and turned into heat energy, then the remaining energy is reflected in different wavelengths. that reflection is what we call color. the darker something is, the less photons are ther
e. complete blackness is the absolute absence of photons altogether. I believe what you're referring to is not speed, but wavelength, which is indirectly proportional to the amount of energy a particular photon is made up of.
in order for a photon to have zero wavelength, it must (at least theoretically) have infinite energy.
about mass: you may have photons confused with electrons. elections have a mass so small that people say they are without mass, but they do. it is called electron mass or Me-.
you may also be getting electrons and photons confused because of the cherenkov effect. that is what happens when a particle travels faster than light IN THAT PARTICULAR MEDIUM. I emphasize that because no other particle besides photons can go the speed of c.
when a particle goes faster than light in a particular medium, a blue light is emitted, called cherenkov radiation. this is why nuclear reactors glow blue.
nuclear reactors release so much energy that when they emit electrons, those electrons are given enough energy to go faster than light in that medium (in this case water), releasing blue light. if you put the reactor in air or a vacuum, this effect wouldn't happen because the speed of light in air
is very close to c, which is the universal speed limit. I'd you did go faster than c, time would go backwards and you would have infinite theoretical mass and probably spagghettify, like with a black hole.
light waves can travel through a vacuum, and do not require a medium. In empty space, the wave does not dissipate (grow smaller) no matter how far it travels, because the wave is not interacting with anything else.
Please is there any instructional material for sounds Waves, Echo, light waves
how far there is hot topic that is boarding me now
linear motion
tell us about it
kinematics disscuss the motion without cuases ...
wow I like what am seeing here I need someone to brush me up in physics in fact I'll say I know nothing
How does the Geiger tube works
Salma Reply
pls he do we find for tension
Belinda Reply
tension is equal to the weight of the object. so for example if something weighs 45 Newtons then the tension in the Rope holding it is 45 Newtons. and because it is in equilibrium if the object is 45N and there are three ropes holding it there would be 15 N of tension in each to equal the weight
does that work for you?
very correct
A prankster applies 450 V to an 80.0 µF capacitor and then tosses it to an unsuspecting victim. The victim’s finger is burned by the discharge of the capacitor through 0.200 g of flesh. What is the temperature increase of the flesh? Is it reasonable to assume no phase change?
Khanh Reply
what is mass
Aliyu Reply
the quantity of matter that a body contains, as measured by its acceleration under a given force or by the force exerted on it by a gravitational field.
I agree wth aliyu shuwa
or in easier terms the amount of stuff in an object (stuff meaning whatever element or material that makes the object heavy) the object composition
an object's resistance to change in motion?
your mass never changes but your weight changes based on the gravitational pull of a system or planet. your mass is just the amount of matter with a certain object
please can someone help, why a bats can fly in the night without heating anything, how does he managed an see in darkness?
...hit an obstacle and has bounced back.
Hi Vincent. From what I can remember and what I've learnt, bats do not have a good eye sight and so they make use of waves, when they send out waves and they do not return back to them, they realise that the site is free of obstacles but if it sends a wave and it returns back, it means it hit an
obstacle and bounced back
So bats make use of waves in place of eye sight. I think but confirm from a few sites .
they us echolocation to make a sort of mental map. many sea animals use the same method. this can also be compared to sonar which works in the same way
y is atom d smallest particle
its a question Lajpat Rai
Google Quantum Physics or refer to the text
atoms are considered the smallest unit of matter. it is further divided into three subatomic particles: protons, neutrons, and electrons.

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Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
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