A material whose K absorption edge is 0.15 Å is irradiated with 0.1 Å X-rays. The maximum kinetic energy of the photoelectrons that are emitted from the K-shell is :
Correct answer: A. 41 keV
- A. 41 keV
- B. 51 keV
- C. 61 keV
- D. 71 keV
Explanation
To determine the maximum kinetic energy of the photoelectrons, we need to calculate the energy of the incident X-rays and the energy corresponding to the K absorption edge. The energy of a photon is given by E = hc/λ, where h is Planck's constant and c is the speed of light.The energy of the 0.1 Å X-rays is calculated as:Eincident = (6.626 x 10-34 J·s)(3 x 108 m/s) / (0.1 x 10-10 m) = 1.986 x 10-15 J = 124 keVThe energy corresponding to the K absorption edge is:EK = (6.626 x 10-34 J·s)(3 x 108 m/s) / (0.15 x 10-10 m) = 1.324 x 10-15 J = 83 keVThe maximum kinetic energy of the photoelectrons is the difference:Ekinetic = Eincident - EK = 124 keV - 83 keV = 41 keVThus, the correct answer is 41 keV. The other options represent incorrect calculations of this energy difference, leading to overestimated or inconsistent values.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Dawn of Modern Physics
Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
Practise Dawn of Modern Physics
739 free Dawn of Modern Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Dawn of Modern Physics questions
A photocell with a constant potential difference of V volt across it illuminated by a point source from a distance of 25 cm. when the source is moved to a distance of 1m. The electrons emitted by the photocell.
The amount of energy needed to remove electrons from the metal surface dependsupon
The relation of uncertainty principle between position and momentum is given by:
If the rate of emission of energy from a star is 2.7 x 10^36 J/sec. The rate of loss of mass in the star will be :
In an experiment, a tungsten cathode that has a threshold wavelength of 2300 Å is irradiated by ultraviolet light of wavelength 1800 Å. The maximum energy of emitted photo-electrons will be:
1.5 mW of 400 nm light is directed at a photoelectric cell. If 0.1% of the incident photons produce photoelectrons, the current in the cell is: