answer all questions please

16A.1 Explain how the permanent dipole moment and the polarizability of a molecule arise. 16A.2 Explain why the polarizability of a molecule decreases at high frequencies. 16A.2(b) Calculate the resultant of two dipole moments of magnitude 2.5D and 0.50 D that make an angle of 120 to each other. 16A.3(b) Calculate the magnitude and direction of the dipole moment of the following arrangement of charges in the xy-plane: 4e at (0, 0), -2e at (162 pm, 0), and -2e at an angle of 30 from the x-axis and a distance of 143 pm from the origin