C#/Db is a half step above C.
G is half a note higher than F#. The full scale is C C# D D# E F F# G G# A A# B C
C Natural is a whole step above B flat. If you look at a piano, a half step above B Flat is B Natural, and one more half step above that is C Natural. So it's a whole step from B Flat to C Natural.
B flat. I picture it on the piano, one key is one semi-tone or half a tone. Two of these makes one whole tone, or one whole step. One half step down from C would be the note B, another half step would then go to B flat. That is one whole step.
augmented
B sharp if it is one and a half step up, but if just half then it is A sharp. -BJ
B (B natural).
C#/Db is a half step above C.
C natural
It is a note a half step above or below the original note (a sharp or flat).
G is half a note higher than F#. The full scale is C C# D D# E F F# G G# A A# B C
G is half a note higher than F#. The full scale is C C# D D# E F F# G G# A A# B C
It is usually written just to the right of the note. A sharp means to raise one half step and flat means to lower one half step.
Sharp (usually a half step above the natural note)
It lowers the note by one half-step/semitone.
it makes the note a half step higher
That would be either called C# or Db.