What is meant by inductive effect?please Describe it

Its a transfer of sigma electron....

+I are the group which donate electron and -I are the group which accept electrons

We treat all the alkly group to  be +I and rest all as -I..

Due to more electonegativity of an atom , not only the the sigma bond shared by it but also adjacent bonds get polarised towards it . It is like 5 people standing in line holding each other's hands, when a strong person at one end pulls his partner , the other neighbours are also displaced from their position butthe effect on 4th is least & no effect on 5th one .