UC知道高中物理,实在是概念忘了,求教!
来源：百度知道 编辑：UC知道 时间：2024/06/27 10:59:12
(a) Lanthanum has two isotopes and . The half-life of is years. In a sample containing both isotopes, the concentration of atoms is 0.1 %. Calculate the rate of decay of in 1 kg of lanthanum. (Avogadro constant = 6 10 23 mole -1).
(b) An X-ray tube operated at a DC potential difference of 40 kV, produces heat at a rate of 720 W. Assume that 0.5% of energy of the electron is converted into X-rays. Calculate
(i) the number of electrons per second striking the target;
(ii) the velocity of the incident electron. The charge-to-mass ratio of the electron, = 1.8 1011 C Kg-1.
(c) When Cesium is illuminated with light of wavelength 546 nm, the maximum speed of the electron emitted is m/s. What is the maximum speed of the emitted electrons when the metal is illuminated by light of wavelength 450 nm?
(d) A hydrogen atom in the n=4 state makes a transition to the ground state, emitting one photon. Calculate the wav
(b) An X-ray tube operated at a DC potential difference of 40 kV, produces heat at a rate of 720 W. Assume that 0.5% of energy of the electron is converted into X-rays. Calculate
(i) the number of electrons per second striking the target;
(ii) the velocity of the incident electron. The charge-to-mass ratio of the electron, = 1.8 1011 C Kg-1.
(c) When Cesium is illuminated with light of wavelength 546 nm, the maximum speed of the electron emitted is m/s. What is the maximum speed of the emitted electrons when the metal is illuminated by light of wavelength 450 nm?
(d) A hydrogen atom in the n=4 state makes a transition to the ground state, emitting one photon. Calculate the wav
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翻译：（1）镧有两个同位素并且半衰期是几年。在包含同位素的样品，原子的集中是0.1%计算1023每摩尔镧1公斤朽烂率。(Avogadro常数=6 1023每摩尔)
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