Daily solar radio flux at six different frequencies in dm, cm and mm wavelength regions has been studied for 182 days from December 1, 1970 to May 30, 1971. It is found that the slowly varying component of the centimeter wave emission correlates well with the physical model of the coronal active regions derived by Sengupta (Sengupta, 1971b) from which, as he showed earlier, most of the solar soft X-rays of wavelength less than 20 A comes. It is also found that the cm wave emission is consistent with the assumption that the emitting regions are optically thin in this wavelength range.