An M.Tech thesis typically focuses on a specific, narrower problem or application, demonstrating the student's ability to apply existing knowledge and techniques over 1-2 years. It may involve some original research but is primarily about practical application. In contrast, a PhD thesis addresses a broader, more complex problem over 3-7 years, requiring significant original research that contributes new knowledge or theories to the field. The PhD thesis involves a deeper level of investigation and a rigorous review process, culminating in a formal defense, reflecting the expectation of making a substantial academic contribution.