The dipole moment of methane (CH4) is zero due to its symmetrical tetrahedral molecular geometry. In CH4, the carbon atom is at the center with four hydrogen atoms arranged around it at the corners of a tetrahedron.
Each C-H bond is polar because of the difference in electronegativity between carbon and hydrogen; however, the symmetry of the molecule causes the dipole moments of the bonds to cancel each other out. The individual bond dipoles are equal in magnitude but opposite in direction, resulting in a net dipole moment of zero.
Therefore, despite the polar bonds present in CH4, its overall molecular structure is nonpolar, leading to a zero dipole moment.