@ apoorv
in the case of ccl4 , they have tetrahedral shape and they are symmetric , so, they have dipole moment as 0 .
in ch2cl2 the polarity vectors of two H atoms add up to cl atoms but vector of one cl atom cancel the effect of anathor cl atom and give it a smaller dipole moment .
now if u compare the both
then the value of dipole moment of ch2cl2 is = 1.59 D
and in the case of ccl4 its 0 ..