Socrative is an easy tool for online assessment and feedback in education, it uses short tests, polls or quizzes.
It can be used during lectures to assess how well students understand what they were just told or shown or whether they remember key points or terms of the lecture.
As a teacher, first you need to register at this page www.socrative.com. After registration, Basic Socrative account is set up, that enables creating different types of quizzes and polls.
Three types of questions can be included in a Socrative quiz: true-false questions, multiple choice questions and short answers. After creating, each quiz needs to be launched in a room with a unique room name, that students use later to connect to the particular room and answer the quiz.
For more information, see here.