Flat (♭)

• A flat is an accidental that indicates a slight decrease in pitch (i.e. moving backward of a semi tone).
• A flat is a symbol (♭, also ‘b’ in type, bemolle) placed in front of a note, decreasing its pitch by a half step; Db (or D♭) is a half step lower in pitch than D.
• To “flatten” a note means to lower its pitch by a half step.
• C, C# / D♭, D, D# / E♭, E, F, F# / G♭, G, G# / A♭, A, A# / B♭, B

Semi tone

The distance between each note (Cromatic Scale) is called "Semi tone".

E.g., Different between C and C#. Similarly distance between C# and D, etc.,

Cromatic Scale

The "Cromatic Scale" defined in 12 tones.

They are
C, C#, D, D#, E, F, F#, G, G#, A, A#, B

Sharp (#)

• A Sharp is an accidental that indicates a slight increase in pitch.
• A sharp is a symbol ('#’ in type) placed in front of a note, increasing its pitch by a half step.
• D# is a half step higher in pitch than D; and D is a half step higher than C#.
• To “sharpen” a note means to raise its pitch by a half step.

Diatonic scale

• The music scale notes are 7, defined by the "Diatonic scale".
• They are C, D, E, F, G, A, B
• These are SA... RI...GA...MA...PA...DA...NI...SA... (CDEFGABC) in Indian music.
• C stands for SA
• D stands for RI
• E stands for GA
• F stands for MA
• G stands for PA
• A stands for DA
• B stands for NI
• C stands for SA