论文部分内容阅读
效率一词在物理学中也被广泛采用.它与原子的选择性吸收有什么联系呢?请看下例: 用粒子轰击原子可使其从基态跃迁到激发态,设原子基态和激发态的能量差为△E,现分别用电子和质子轰击质量为M的静止原子.试问欲使上述跃迁发生,所需的最小动能是否相等?(此题选自上海市第三届中学生物理竞赛试题) 解:设m为入射粒子质量,v_1和v_2分别为入射粒子在与原子碰前和碰后的速度,u为原子碰后的速度.由碰撞前后动量及能量守恒可得
The word efficiency is also widely used in physics. What does it have to do with the selective absorption of atoms? Look at the following example: Atoms can be bombarded with particles to make them transition from the ground state to the excited state, with the ground state and the excited state of the atom. The energy difference is △E, and electrons and protons are now used to bombard a stationary atom of mass M. Try to make the transition occur, and whether the minimum required kinetic energy is equal? (This question is selected from the 3rd Shanghai Junior High School Physics Contest) Solution: Let m be the mass of the incident particle, v_1 and v_2 are the velocity of the incident particle before and after collision with the atom, u is the velocity after the atom collision. The momentum and energy conservation before and after the collision are available.