The photon energies used in different types of medical x-ray imaging vary widely, depending upon the application. single dental x rays use photons with energies of about 25 {\rm kev}. the energies used for x-ray microtomography, a process that allows repeated imaging in single planes at varying depths within the sample, is 2.5 times greater.

what are the wavelengths of the x rays used for these two purposes? answer in m
\lambda_{\rm dental}
\lambda_{\rm microtomography}

Asquare isothermal chip is of width w=5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at tinf=15 °c. from reliability considerations, the chip temperature must not exceed t=85 °c. if the coolant is air and the corresponding convection coefficient is h=200 w/m2 x k, what is the maximum allowable "power" of the chip? if the coolant is a liquid for which h=3000 w/m2 x k, what is the maximum allowable power of the chip?