Which one of the following is not a property of the X-rays?

Which one of the following statements about X-rays is not true ?

Which one of the following wavelengths corresponds to the wavelength of X-rays?

Which of the following rays are used in the diagnosis of intestinal diseases?

Which one of the following statements with regard to the ultraviolet light is not correct?

Which one of the following is used for determining the structure of crystal?