2024-01-12
最小距离算法首先计算每一个类别的中心，这个中心指的是该地物在图像空间上的中心。
A.正确
B.错误
错误
A photon having 40 keV scatters from a free electron at rest.What is the maximum energy that the electron can obtain？（）
类别: 题库 | 2024-01-13
A photon of wavelength 2.0 nm Compton-scatters from an electron at an angle of 90°.What is the modified wavelength？（）
The momentum of photons corresponding to the minimum wavelength emitted from x-ray tube whose operating voltage is 120 kV is（）
An X-ray tube operates at 100 kV.The maximum speed of electrons striking the anticathode is（）
If the K， L， and M energy levels of Pt are 78000 eV， 12000 eV and 30000 eV， respectively， the wavelength of Ka line from Pt is（）
When the atomic number of the anticathode is 79， the frequency of Ka line is（）
In Zn the ionization energy of K shell is 9.659 KeV and L shell 1.021 KeV.The kinetic energy of the Auger electron emitted from the L shell is（）
Liquid helium（atomic weight 4.003） has a density r= 0.13 g/cm3.Estimate the radius of a He atom， assuming that the atoms are packed in the densest possible configuration， which fills 74% of the space.（）。
Through what angle is a 4 MeV a particle scattered when it approaches a gold nucleus with a impact parameter of 2.6 X 10-13 m？（）。
The energy of a hydrogen atom in the first excited state is（）
2024-01-13
