The wavelength of a probe is roughly a measure of the size of structure that it can probe in some detail. The quarks structure of photons and neutrons appears at the minute length -scale of `10^(-15)m` or less. This structure was first probed in early 1970's using high energy electron beam produced by a linear accelerator at Stanford's USA. Guess what might have been the order of energy of these electron beams (Rest mass energy of electron=0.511 eV).

Explanation

Momentum of the particle of `lamda=10^(-15) m` is given by
`p=h/lamda=(6.63xx10^(-34)Js)/(10^(-15)m)=6.63xx10^(-19)"kg ms"^(-1)`
`p=E/cimpliesE=pc`
`E=6.6xx10^(-19)xx3xx10^8`
`impliesE=1.989xx10^(-10)J = 1.24BeV`
Thus, electron energies from the accelerator must be of the order of a few Be V.