Oracle Database Administration

We received a mail from customer stating that - Heavy business activity today after 10AM and especially between 16:00 to 17:00 hrs where we see 47 archive log switch and 100GB archive generated today in today after 10AM. Using below sql query you can check in which interval more archive log generated in the database. col day for a12 set lines 1000 set pages 999 col "00" for a3 col "01" for a3 col "02" for a3 col "03" for a3 col "04" for a3 col "05" for a3 col "06" for a3 col "07" for a3 col "08" for a3 col "09" for a3 col "10" for a3 col "11" for a3 col "12" for a3 col "13" for a3 col "14" for a3 col "15" for a3 col "16" for a3 col "17" for a3 col "18" for a3 col "19" for a3 col "20" for a3 col "21" for a3 col "22" for a3 col ...