Answer
Radiation in part (a) would be detected.
Work Step by Step
Using figure 4.6 we can see that x-ray can detect wavelength from 10^-11 to 10^-8 and frequencies from about 10^16 to 10^19. The radiation in part (a) is detectable because it has a wavelength of 0.86 x 10^-9 meters or 0.86 nanometer which is between 10^-11 and 10^-8. Part (b) however is not detectable because its frequency is 6.4 x 10^11/s which does not lie between the frequencies from 10^16 and 10^19.
