The viola is also a bowed string instrument. It is slightly larger in size and it has a lower and deeper sound than a violin.

 

The viola is held in the same way as the violin; however, due to its larger size, some adjustments must be made to accommodate to it. The viola, just like the violin, is placed on top of the left shoulder between the shoulder and the left side of the face (jaw). Because of the viola's size, violists with short arms tend to use smaller-sized violas for easier playing. The most immediately noticeable adjustments that a player accustomed to playing violin has to make are to use wider-spaced fingerings. 

 

The viola's four strings are normally tuned in fifths: the lowest string is C (an octave below middle C), with G, D and A above it. This tuning is exactly one fifth below the violin, so that they have three strings in common—G, D, and A—and is one octave above the cello.

 

en.wikipedia.org/wiki/Viola