Chemical Bonding and Molecular Structure Part 1

Here µ‌total ‌=µ1+µ2≠0µ‌total ‌=µ1−µ2=0µ‌total ‌=µ1+µ2≠0µ1+µ2+µ3=µ4
µ‌total ‌=0
In NO2 and O3 have permanent dipole moment as both of them are not symmetric molecule.
In CO2 and SiF4 each individual bond c=O and S−−F have dipole moment but because of symmetric structure individual dipole moment get's cancelled.