  We experimentally investigate the escape from a metastable state over a
fluctuating barrier of a physical system. The system is switching between two
states under electronic control of a dichotomous noise. We measure the escape
time and its probability density function as a function of the correlation rate
of the dichotomous noise in a frequency interval spanning more than 4 frequency
decades. We observe resonant activation, namely a minimum of the average escape
time as a function of the correlation rate. We detect two regimes in the study
of the shape of the escape time probability distribution: (i) a regime of
exponential and (ii) a regime of non-exponential probability distribution.
