Hi, Iam having trouble understanding (or actually picturing) things I have learned, now that I look back at it. When the photon have a higher energy, what does this mean besides the frequency is higher? Does the photon "cover" a smaller area because it turns up and down so quick so it does not have much time to go "far up and far down"? Also, about the Neutron - Boron inteaction (the capture). When the Neutron has a high energy the cross section is low, but when the neutron has low energy the cross section is high. Is there an intuitive answer to this? Basically, what happens or what is the difference when the particle have a higher energy 1) Photons 2) Charged particle (protons and electrons), e.g. does the electric field around them expand 3) Neutral particles (neutrons) Regarding #2, I do know that when you accelerate a charged particle to light speed, it will never reach light speed, instead its mass would expand instead (E=mc^2). But what else happens, the classical-physics would say it would have a higher speed, e.g. will be in point A in less time. But the relativistic answers are interesting! Also, the electron is not a particle right? Its like a cloud? This makes it more interesting to what happens when it is accelerated. Thank you!