Dipole moment of phenol is smaller than that of methanol. Why ?

Explanation

Dipole moment depends upon the polarity of bonds. Higher the polarity of bonds in molecule, higher will be its dipole moment. In phenol carbon is `sp^(2)` hybridised and due to this reason benzene ring is producing electron withdrawing effect.
On the other hand, carbon of methanol is `sp^(3)` hybridised and produces electron releasing effect (+I effect). Thus, `C-O` bond in phenol is less polar than C-O bond in methanol and therefore, the dipole moment of phenol is smaller than that of methanol.