What is the log backup schedule?
This depends on how your log backups are set up.  If you are using Maintenance Plans, then look up the specific plan under Management->Maintenance Plans in your SSMS Object Browser.  If you are using a SQL Agent Job, then you'll need to look at the schedule attached to that specific job by opening the job and looking at the schedule on the schedule page.

You can also query the msdb.dbo.backuphistory table to see when your log backups have been taken with the following query:

select 
    database_name
    ,backup_start_date
    ,backup_finish_date
from msdb.dbo.backupset
where type = 'L'
order by database_name,backup_start_date desc