This is a sixteenth note.
It lasts for one quarter of a beat.
There are four sixteenth notes in one beat
There are 16 sixteenth notes in one bar of * time.
Once you are comfortable playing sixteenth notes on a single pitch, try using them to play scales and arpeggios, as shown in the following example which demonstrates the G, C and F major scales, and the F major arpeggio played in sixteenth notes.
Here are some examples which make use of sixteenth notes. Take them slowly at first and count as you play. Tap your foot on each beat and remember that there are four sixteenth notes per beat. Becaues the notes are closer together here, you will need to breathe after a quarter note, or even an eighth note sometimes.