Based on the numerical solution of linear problem on diffraction of a femtosecond plane wave on a weakly absorbing spherical particle, the spatial and temporal structure of the light field inside a sphere is studied. It was found that there exists a multimode regime of excitation of whispering-gallery (WG) modes. The effect of the spectral width ratio between the excited WG mode and the laser pulse is analyzed. It is shown that the decrease of this ratio at transition from a monochromatic wave to a femtosecond pulse leads to a significant decrease of the high-intensity internal field at the points of its maxima. The possibility of obtaining stimulated radiation in a microparticle at the Stokes and third-harmonic frequencies is shown.