If a source is emitting particles at a rate of 15,000 particles per second, what is
the flux at 30 cm away from the source?
It depends upon the angular distribution of the emitted particles. If you are talking about radioactive decay, unless the nuclei are aligned (which is extremely unlikely) the emission will be isotropic, i.e, the same in all directionns.
The flux (emission per area) 30 cm away will then be
15,000 part/sec/(4*pi*R^2),
where R = 0.30 m
isnt the area of a circle Pi*R^2?
To calculate the flux at a certain distance from the source, we need to first understand what flux is. Flux refers to the flow per unit area or the amount of something passing through a given surface in a given time.
In this case, the source is emitting particles at a rate of 15,000 particles per second. The flux would then be the number of particles passing through a unit area per unit time.
To determine the flux at a distance of 30 cm away from the source, we need to take into consideration the relationship between the surface area of a sphere and the distance from its center.
The surface area of a sphere is given by the formula: A = 4πr², where A is the surface area and r is the radius of the sphere.
In this case, the distance from the source is 30 cm, which means the radius (r) will be half of that, so r = 15 cm.
Now, we can calculate the surface area of the sphere:
A = 4π(15 cm)²
A = 900π cm²
The flux is the number of particles passing through a unit area per unit time, so the flux at a distance of 30 cm away from the source would be:
Flux = number of particles / surface area
Flux = 15,000 particles / 900π cm²
To find the exact value of the flux, we can use a calculator or approximate the value of π to 3.14. Let's use the exact value for now:
Flux ≈ 15,000 / (900π) particles per cm² per second