In this thesis we studied coherent effects in a cold atomic gas of rubidium isotope 87Rb interacting with two lasers. A theoretical background on the interaction of two lasers with an atom in lambda configuration is presented. One of the lasers is a continuous-wave laser, while the other is a pulsed, femtosecond laser. Rubidium transitions 52S1/2(F = 1) → 52P3/2(F’ = 2) and 52S1/2(F = 2) → 52P3/2(F’ = 2) were chosen and used, as they correspond to a lambda configuration. Also presented is a short theory of laser cooling and trapping, which is used to make a cloud of cold rubidium atoms for the experiment of coherent effects. We explain the methods of frequency stabilization of continuous-wave and femtosecond lasers, needed for measurements of high precision. The results were acquired by measuring laser radiation force on a rubidium cloud, as well as by measuring laser induced fluorescence of the cloud interacting with the lasers. We compared the measurements to the theoretical predictions and they correspond very well to the numerical models. We conclude that the femtosecond laser is a very useful tool which can be used in the experiments focused on coherent effects, as well as continuous-wave lasers have been used.