1.in an x-ray tube,electrons striking a target are brought t

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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.

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倍,最高频率变为2Fo
公式中的h为普朗克常量γ,γ为所求波的频率,U为首次所加电压,e为一个电子所携带的电量
2.一个质量为M的物体用细绳子悬挂在汽车内的棚顶上.某一时刻,汽车左转并依恒定的速率V绕半径为R的圆运动.求细绳与竖直线的夹角G的准确表达式.
根据匀速圆周运动的公式可得到
MV²/R=Ma ①
根据牛顿第二定律得到
MgtanG=Ma ②
解此方程组得到
tanG=V²/(gR)
∴G=arctan[V²/(gR)]

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