Questions tagged [unit-conversion]

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What is the relationship between the magnetic units oersted and tesla?

How are the units oersted and tesla related? For example, how would you express $20\:\mathrm{Oe}$ in tesla?
1k views

How to convert intensity arbitray units to percentage in a XRD data?

In powder x ray diffraction result contains mainly two values 2theta and intensity where 2theta is in degree's and intensity is in arbitrary unit ...
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Confusion on electron volt and Kelvin?

If an element A has a binding energy of X eV with element B, can it be said that it is equivalent to X*11600K as 1 eV approx equals 11600K. I do not think this is correct as temp. is linked to the ...
578 views

What does J cm-1 stand?

For an optical component, I got following number as an optical damage threshold from the company, damage threshold = 10 Jcm-1,20ns, 20Hz It looks like 20ns is ...
50 views

In this energy conservation problem, why are the answers different with different units? [closed]

Really basic question, but basically I'm given a change in height in centimeters (that's how I measured it). From that, I'm supposed to find the initial kinetic energy. $KE_i = PE_f$ After doing ...
198 views

Conversion from PPBV to PPBM [closed]

What is the conversion between PPBV and PPBM? I have a database that includes values of Parts-per-billion-by-volume (PPBV) as a function of altitude. I've been asked to convert this to "parts-per-...
293 views

Proper units for physical quantities when $\hbar$=$1$

How to deal with the units of quantities if $\hbar=\tfrac{h}{2\pi}=1$? For example, the energy $E=\hbar\omega$: If I have chosen $\hbar=1$, how do I use the units to properly differentiate between ...
1k views

The Kelvin-Celsius problem

Let's suppose we have temperatures 30°C and 35°C. Converting them to Kelvin we have 303.15K and 308.15K. In the second case, the temperature difference is 5K. While in first case, temperature ...
76 views

Is there a software to convert units for quantities and equations? [closed]

For example, Often I end up with a complicated equation that uses non-standard units. In these equations, Temperature is in eV and Magnetic field is in Gauss. I need to convert my equation to another ...
74 views

Fine structure constant and unit conversion [closed]

In a paper I'm reading, the author writes down the following formula: $$\Gamma=\dfrac{\alpha^2}{576\pi^3}\dfrac{\left(4+z\right)^2}{z}\dfrac{m^5}{m^2_\pi f_\pi^2}$$ $\Gamma$ is a function of $m$ (in ...
1k views

Classification of plane angle as fundamental or derived

I recently started with my high school studies and the chapter I am stuck at is units and measurements. I was told about two types of physical quantities and my teacher gave me the following ...
24k views

What is the difference between emu and esu?

My textbook contains the following two statements: In the CGS system the unit of charge is electrostatic unit of charge (E.S.U). It is also called Stat Coulomb (StatC). In the CGS system, the ...
2k views

Converting PSI to Velocity [closed]

The question I'm asking is pretty much: How do you convert PSI to Velocity? Everywhere I look it says You can't, but can you? And what would you need to know to ...
136 views

Sudbery's Quantum Mechanics and the Particles of Nature, Chapter 1, Problem 2: Calculate the mass of the electron [closed]

I'm currently working on the problems for Chapter 1 of Quantum Mechanics and the Particles of Nature: An outline for mathematicians by Anthony Sudbery (Cambridge University Press, 1986; reprinted (...
606 views

Bohr's model and positronium

I was trying to get an order of magnitude estimate for the radii and energies of positronium using the Bohr's model. I did find a few places where they have used the reduced mass to replace the ...
71 views

Easy unit conversion in Kerr metric

I would like to use Kerr metric in Boyer-Lindquist coordinates in geometrized units with mass of the black hole normalized to $M=1$. I am embarrassed to admit, but I can't seem to figure out how to ...
3k views

How to express a mechanical force field in the units of electric fields?

Electrostatic fields have a unit $\frac{V}{m}$ (volts per meter) and the mechanical force fields (including gravitational field) have a unit $\frac{m}{s^2}$. If we exclude gravitational force from ...
112 views

Converting $W/m^2$ unit [duplicate]

In my equation I have a unit measured in MET found here $1MET=58.2 W/m^2$. But my other parameter which is metabolic heat generation is measured in $W/m^3$ . I want to convert $W/m^2$ units ...
696 views

Why does the vacuum permeability have the value of $\pi$ in it?

The vacuum permeability, or the capability of the vacuum to permit magnetic field lines, contains the value of $\pi$. Why? What does this have to do with the ratio of a circle's circumference to its ...
111 views

Lorenz Gauge Dipole Potentials Formulation In SI Units? [closed]

After hunting in vain* for a documented closed form solution (ie: no integrals or differentiation in the formula) for $\phi$ in terms of A under the Lorenz condition, of an electrically short dipole (...
372 views

Pi switching from 3.14 to 180°

The task goes as following: Calculate the amount of charge $Q$ of a unevenly charged semicircular ring with radiuses $a$ and $b$ if $\eta=\eta_0\sin\phi, 0<\phi<\pi$. I started off by ...
10k views

How do I use the kinetic energy formula using mass as lbs and velocity as mph?

I understand that the formula for kinetic energy is: $(1/2)mv^2$, which is equal to 1 Joule or 1 N-m. If I want $m$ to be my weight (say 150lbs) and $v$ to be 40mph how do I apply it to this formula? ...
250 views

Units in gravitational N-body simulations

I use a code in Python to simulate a binary system interacting through gravity. You can find it here; The code works fine. I am however having problems with the units of length and velocity. I ...
660 views

726 views

conversion of units

I have a quantity that I need to convert to different units. First, I need to note that the value is in the natural units system. The quantity is in cm^-1 (or, to be accurate, $cm^{-1}\hbar c /k$, ...
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Speed to power conversion

Here it is stated that there is a cubic relationship between fan speed and power consumption (Pfan ∝ FanSpeed^3). I have the fan speed (m/s), but I need to convert it into power (W). How can I compute ...
2k views

How to derive velocity pressure in English units?

I know that velocity pressure can be calculated from dynamic pressure according to the potential energy of pressure (from Bernoulli's equation): $$P = \frac{1}{2} \rho \overline{V}^2$$ where P = ...
69k views

What is the fundamental units for coulomb? [closed]

Everything I saw suggests coulomb has no fundamental units. So then how is Newton/Coulomb equivalent to Volt/meter?
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Recalculating lux from EV

I have to calculate amount of light from IR emmiter. The only equipement, that I can use is Sekonic Light Meter like this one: http://www.ebay.com/bhp/sekonic-l-358 The problem is that i need to have ...
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Pressure equation working to get units kg m/s$^2$, but stuck?
Why does $kg/m^3 \cdot m/s^2 \cdot m$ become $kg\,m/s^2$ (i.e. one newton) When I do the working, I get $kg/(s^2 m)$ (i.e. metres is on the bottom rather than the top) My working is: \begin{align} ...