  This paper presents an analysis of the correlation between the far-infrared
(FIR) and the radio emission of starburst galaxies. Data for interacting
galaxies, many of which are undergoing a starburst, and for normal galaxies
have been analysed and compared in order to test for any influence of the
star-formation activity on the ratio between the FIR and the radio emission at
2.4 GHz, $\q24$. No statistically significant indication for such an influence
has been found: There is neither a significant difference between $\q24$ of the
two samples nor a dependence of this ratio on the starburst strength. This
observational fact is unexpected because of the different physical conditions
and the short time-scale of the star-formation activity in a starburst. In
order to interprete the observations the FIR and the radio emission during a
starburst have been modeled. The following conclusions could be drawn from the
observed constancy of $\q24$: A strong and fast ($\approx 10^7$ yr) increase of
the magnetic field at the beginning of the starburst is required in order to
maintain a constant $\q24$. Otherwise the strong Inverse Compton losses that
are due to the intense radiation field in a starburst would lower the
synchrotron emission drastically resulting in a value of $\q24$ significantly
higher than the observed one. Furthermore, the time-scale of the variation of
the star-formation rate has to be longer than some $10^7$ yr. For lower values
the different time-scales of the FIR and the radio emission produce large
fluctuations of $\q24$.
