Answer:
In music and music theory, the beat is the basic unit of time, the pulse, of the mensural level. The beat is often defined as the rhythm listeners would tap their toes to when listening to a piece of music, or the numbers a musician counts while performing, though in practice this may be technically incorrect.
As an example, the note B is represented on the third line of the treble clef staff. The note B-flat is indicated with that same note head with a ♭ symbol placed to the left of it. The ♭ symbol universally indicates a flat note. It tells a player to sound a pitch half a tone lower than the written note.
like this B♭
