Difference between Single & First in LINQ

Single:

DBContext db = new DBContext();
Customer customer = db.Customers.Where( c=> c.ID == 5 ).Single();

The single  throws exception if multiple records are returned.

The First method provides the first record returned by the query.

First

BContext db = new DBContext();
NewsItem newsitem = db.NewsItems.OrderByDescending( n => n.AddedDate ).First();