The scrum master is the leader as well as coach of the Scrum team. The scrum master is responsible to serve and protect his team from any kind of distractions that could affect their performance. The main role of the scrum master is to motivate his team to achieve the sprint goal. He is focused to build a self-organized and motivated team where each member is familiar with the implementation of Agile and Scrum principles and applications.
The scrum master keeps a proper check on the scrum team if they are executing committed tasks properly. He is also responsible to increase the efficiency and productivity of the team so that they can achieve the sprint goal effectively.