Explanation
Activity Monitor displays information about SQL Server processes and how these processes affect the current instance of SQL Server.
Activity Monitor is a tabbed document window with the following expandable and collapsible panes:
Overview, Active User Tasks, Resource Waits, Data File I/O, and Recent Expensive Queries.
The Activity User Tasks Pane shows information for active user connections to the instance, including the following column:
* Login: The SQL Server login name under which the session is currently executing.
The Recent Expensive Queries Pane shows information about the most expensive queries that have been run on the instance over the last 30 seconds, including the following column:
* CPU (ms/sec): The rate of CPU use by the query
References: https://technet.microsoft.com/en-us/library/cc879320(v=sql.105).aspx