  We study the radio--FIR correlation between the nonthermal (synchrotron)
radio continuum emission at \lambda 90 cm (333 MHz) and the far infrared
emission due to cool (~20 K) dust at \lambda 70\mu m in spatially resolved
normal galaxies at scales of ~1 kpc. The slope of the radio--FIR correlation
significantly differs between the arm and interarm regions. However, this
change is not evident at a lower wavelength of \lambda 20 cm (1.4 GHz). We find
the slope of the correlation in the arm to be 0.8 \pm 0.12 and we use this to
determine the coupling between equipartition magnetic field (B_{eq}) and gas
density (\rho_{gas}) as B_{eq} \propto \rho_{gas}^{0.51 \pm 0.12}. This is
close to what is predicted by MHD simulations of turbulent ISM, provided the
same region produces both the radio and far infrared emission. We argue that at
1 kpc scales this condition is satisfied for radio emission at 1.4 GHz and may
not be satisfied at 333 MHz. Change of slope observed in the interarm region
could be caused by propagation of low energy (~1.5 GeV) and long lived (~ 10^8
yr) cosmic ray electrons at 333 MHz.
