As other people have commented above, using TRUNC will prevent the use of indexes (if there was an index on TIME_CREATED). To avoid that problem, the query can be structured as
SELECT EMP_NAME, DEPT
FROM EMPLOYEE
WHERE TIME_CREATED BETWEEN TO_DATE('26/JAN/2011','dd/mon/yyyy')
AND TO_DATE('26/JAN/2011','dd/mon/yyyy') + INTERVAL '86399' second;
86399 being 1 second less than the number of seconds in a day.