Yellow light is used in a single slit diffraction experiment with slit width of $0.6 \mathrm{mm}$. If yellow light is replaced by X-rays, then the observed pattern will reveal,

For diffraction pattern to be observed, the dimension of slit should be comparable to the wave length of light. In other words, diffraction is obtained when the slit width is of the order of wavelength of light (or any electromagnetic wave) used. Here, wavelength of X-rays  $(1-100\mathrm{\AA })<<\mathrm{slit} \mathrm{width} (0.6 \mathrm{mm})$. Therefore, no diffraction pattern will be observed.