Thanks for that - that will be useful.
However, if I have a shield at a distance from a magnet, how do I calculate the field at that distance?
In a related question, if I have two magnets, how do I calculate the field strength at any point between them - is it merely by superposition or are...
Thank you for your replies.
That sounds useful, though unfortunately I'm restricted in terms of power supply in this setup, so I need to go with the most energy efficient option and avoid a current conductor of any sort if possible.
The Hall probe will be useful for measuring, though...
Hi everyone,
I have two questions related to magnetic fields.
Firstly, if I have two bar magnets with opposite poles facing each other, ie NS - NS, how do I measure the magnetic field strength at any point between the two magnets?
Secondly, how would I shield the magnetic fields of the...
Looking at the Friedmann equation
H^2=\left[\frac{\dot{a}}{a}\right]^2=\frac{8\pi G\rho}{3}-\frac{kc^2}{a^2}
and considering positive curvature, then for the limit where the second term dominates, we're left with
\left[\frac{\dot{a}}{a}\right]^2=-\frac{kc^2}{a^2}
This implies a complex...
Homework Statement
The first part of this question deals with interstellar gas collisions at a certain velocity, and the resultant temperature of the cloud is obtained.
Then this question:
The main coolant has the following radiative loss rate
\Lambda=n_H10^{-28}T_{gas} \text{erg...
Okay, so differentiating and setting to zero gives
\frac{dN}{dM}=10^{34}C\frac{d}{dM}\left[M^{32}exp(-M^2)\right]=0
giving
32M^{31}exp(-M^2)=2M^{33}exp(-M^2)
which simplifies to
M=4
So how do I interpret that? It only really makes sense if it's in units of Msun..
While that method...
Well, I'd say that would be
(Total number of photons produced by all stars of given mass M) = (Number of photons produced by a star of mass M) x (Number of stars of mass M).
Or in symbols
N_{ph-tot}(M_*)=N_{Lyc}(M_*)*N(M_*)
And that would give
N_{ph-tot}(M_*)=10^{34}CM_*^{32}exp(-M_*^2)...
Looking at the expression I got for \frac{dN}{dM}, and assuming we're integrating from zero to infinity, the integral looks like
-2C \int_0^{\infty}M_{*}\frac{1}{exp(M_{*}^2)}dM_{*}
which looks quite like the formula given,
\int_0^\infty x^n\frac{1}{exp(x)-1}dx
except for the -1 on the bottom...
No, your method is fine. The Force term is given by F=mg.
You said you put your zero point in the centre of the ruler. But the question says that the centre is at 3.0cm. Your calculation for the counterclockwise moment is still correct though, as the zero point is 3cm from the fulcrum.
Homework Statement
In a particular star forming cloud the initial mass function (IMF) is given by
N(M_{*})=Cexp(-M_*^2)
where C is a normalisation constant. (The IMF describes the initial relative number of stars of different masses). Assuming that the number of hydrogen Lyman continuum...
Thank you.
I should have said that I was working with velocities and temperatures of chromospheric winds, not just the temperature of the chromosphere. The wind would be anisotropic, as it is being ejected from the star, but the turbulent velocity of the particles within the wind would be...