Final answer:
True, the penetration power of an x-ray beam is determined by its voltage and is expressed as kilovolt peak (kVp). Higher voltage settings increase the energy of the electrons and consequently the x-ray photons, allowing greater penetration through materials, which is vital in x-ray imaging.
Step-by-step explanation:
The statement that the penetration power of an x-ray beam is determined by its voltage and is expressed as kilovolt peak (kVp) is true. When electrons are accelerated through a potential difference measured in volts, they acquire energy equivalent to that potential, with units of electron volts (eV). For instance, accelerating electrons through a 50.0-kV potential will result in the production of 50.0 keV electrons and consequently 50.0 keV x-ray photons. These x-ray photons have the energy to penetrate materials and the higher the energy, the greater the penetration. This concept can be seen in medical imaging, where different kVp settings are used depending on the part of the body being examined and the material's density.
When an electron's energy is entirely converted to photon energy, an x-ray with the highest possible energy is produced, exemplifying the conservation of energy principle where electric potential energy converts to kinetic energy and then to photon energy. For a given potential, the maximum x-ray energy produced is equivalent to the accelerating voltage, hence a 100-kV potential produces a maximum of 100 keV x-ray photons. Variability in x-ray tubes allows for adjustable voltages which can alter the penetration capability of the produced x-rays for different imaging needs.