This app is useful for practising mcqs on the site www.geeksquiz.com/ . The site has various quizzes bifurcated on the basis of topics. For practising and testing our skill, we generally want to attempt quiz having questions from various topics instead of just one. The app gives user an option to select as many number of topics and then answer (at maximum) 20 questions (which are mix of the topics selected). Every quiz will be alloted a maximum time in which it must be finished. Also, score as per the user's input will be calculated and Discuss option is there to see the correct answer and explanation.
You can try it out from chrome store using the link here.