Maybe. Depends on the predicate, the index key columns and the rest of the query. It's not as simple as you're making out.
There's a lot of posts on indexes and index usage on my blog. https://www.sqlinthewild.co.za/index.php/category/sql-server/indexes/
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability