The concept is quite very simple & comprehensible. Take your case, u changed ur. job in the mid of the current financial year, But, u got your salary from ur. ex-employer, that means u earned for that period and now, u changed ur. job and started drawing /earning from ur. new job, u club both the incomes, if the same goes beyond the exemption limit, u keep urself ready to pay tax, if the its below the limit, then vice-versa, means no tax payment. Is it clear ?