Hey, My book says: When an electron strikes the target metal it is attracted by the positively charged nuclei, and hence it loses speed and hence emits a photon of X-ray. That doesn't make sense to me. We learnt that in centripitel acceleration, that the speed of the object being centripitally accelerated stays the same, and this is the case with this.. the electron is being centripitally accelerated by the nuclei and hence it shouldnt loose speed. Can someone explain to me why it loses speed? BTW: I know this isnt a homework or coursework question, but one of the people kept on moving my previous questions which i posted under the general physics forum... SO DONT MOVE THIS ONE OR OTHERWISE COME TO A CONCLUSION AS TO WHAT IS COURSEWORK QUESTIONS AND WHAT IS GENERAL PHYSICS! THIS QUESTION WASNT ASKED AS HOMEWORK! IM JUST WONDERING! BUT MY PREVIOUS TWO QUESTIONS GOT MOVED!