For an X-ray machine radiation is needed with a typical wavelength of 11.9 . This is generated by colliding an electron beam with a target consisting of heavy atoms. Assuming the electron beam is accelerated in a vacuum tube and that all its energy is converted into radiation, i.e. photons, a) What is the potential voltage difference needed to accelerate the electron beam? Assume initial velocity is and energy of the electrons are negligible. b) What is the de Broglie wavelength of the accelerated electron just before it hits the target