Methane CH4 is a tetrahedral molecule with four C-H bonds. The dipole moment of a molecule is the measure of its polarity, which is the product of the charge and the bond distance between the atoms. It is represented by the symbol and is measured in Debye units D .In the case of methane, the electronegativity difference between carbon 2.55 and hydrogen 2.20 is small, resulting in a small bond dipole. However, due to the symmetric tetrahedral geometry of the molecule, these bond dipoles cancel each other out. As a result, the net dipole moment of methane is zero.In general, to calculate the dipole moment of a molecule, you need to consider both the bond dipoles and the molecular geometry. The bond dipole is calculated as the product of the charge difference between the atoms and the bond distance. Then, you need to sum up the bond dipoles considering their directions, taking into account the molecular geometry. If the molecule has a symmetric geometry, like methane, the dipole moment can be zero even if individual bond dipoles are present.