题目

1.in an x-ray tube,electrons striking a target are brought to rest,causing x-rays to be emitted.in a particular x-ray tube,the maximum frequency of the emitted continuum x-ray spectrum is F0,if the voltage across the tube is doubled,the maximum frequency is?
2.an object of mass M hands from a string that is fixed to the ceiling of a car.At the instant shown above,the car is moving into the plane of the page at constant speed V as it turns to the left around a horizontal curve of radius R.what is the correct expression for the angle G of the string with repsect to the vertical?
图就是一个小球M被一根右倾的绳子吊住,绳子和铅垂线成G角.

提问时间：2020-12-25

答案

1.在X射线管中,电子射击固定的靶子,导致X射线的产生.在一个特定的X射线管,发出连续X射线谱的最高频率是Fo,如果在管子中的电压增加一倍,最高频率变为多少?根据普朗克定律E=hγ=QU=eU=Fo可得如果在管子中的电压增加一...