We have computed the ground and excited state energies and the wave functions of a spherical quantum dot with finite potential barrier in the presence of magnetic field. The oscillator strength, the static dipole polarizability and the refractive index changes are investigated as a function of dot radius and magnetic field strength. The results show that the energy state, the oscillator strength, the static dipole polarizability and the refractive index changes are strongly affected by the magnetic field strength and dot size. It is found that while the magnetic field strength increases, the static polarizability decreases strongly.