Transact SQL :: Queries To Simulate INTERSECT And EXCEPT But With Records In Same Table

I have a table (let's call it MyTable) that consists of four fields:

Id, Source, FirstField, and
SecondField, where Source only takes one of two values:
Source1 and Source2.
The records in this table look as follows:

Id
Source
FirstField
Secondfield

1
Source1
Product 3 name
Product 3 description

[code]...

I need to return, using 3 different T-SQL queries:

1) Products that exist only in Source2 (in red above)
2) Products that exist only in Source1 (in green above)
3) Products that exist both in Source1 and Source2 (in black above)

For 1) so far I've been doing something along the lines of SELECT * FROM MyTable WHERE Source=Source1 AND FirstField NOT IN (SELECT DISTINCT (FirstField) FROM MyTable WHERE Source=Source2)

I have read about INTERSECT and EXCEPT, but I am a little unclear if they could be applied in this case out of the box.