Potential Difference for X-Ray Emission

AI Thread Summary
The minimum potential difference required for X-ray emission at a frequency of 1.61x10^16 Hz can be calculated using the equation V = hf/e, where E is the energy of the photon, h is Planck's constant, f is the frequency, and e is the charge of an electron. The energy of the photon is determined to be approximately 1.07 x 10^-17 J. The discussion clarifies that potential difference is indeed measured in volts and is essential for accelerating electrons in an X-ray tube. The process of X-ray emission primarily involves bremsstrahlung radiation, where the kinetic energy of electrons is converted into photon energy upon striking the anode. This understanding is crucial for calculating the necessary potential difference in X-ray applications.
steven10137
Messages
117
Reaction score
0
[SOLVED] Potential Difference argh ...

Homework Statement


What is the minimum potential difference that must be applied across an X-ray tube to observe a line of frequency 1.61x10^16Hz


Homework Equations


OK well we can define potential difference as the amount of energy required to emit this X-ray yeah?


The Attempt at a Solution


<br /> \begin{array}{l}<br /> E = hf \\ <br /> = \left( {6.63 \times 10^{ - 34} } \right)\left( {1.61 \times 10^{16} } \right) \\ <br /> = 1.07 \times 10^{ - 17} J \\ <br /> \end{array}<br />

But I thought that potential difference was measured in volts?

Just need clarification here
Thanks
Steven
 
Physics news on Phys.org
The x-ray emission in an x-ray tube is generally brake radiation. This is emitted by electrons when they are stopped at the anode. The electrons are accelerated due to potential difference after they are emitted by the cathode until they reach the anode. There, the KE of an electron is converted into the energy of a photon. For simplicity, let’s assume that all the KE of an e- is converted into one x-ray photon.

Then E=hf, is the energy of the photon, which is equal to the KE of the e- after it was accelerated across the tube. Work done on e- = V*e, where e is the magnitude of the electronic charge, and V is the potential difference.

Then, V*e=hf => V=hf/e should give you the minimum potential difference.

Again, this is only if the process of emission is that of brake radiation, which is generally what happens in x-ray tubes.
 
thanks!
makes perfect sense
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top