Explore the third session of the Radiative Processes lecture series delivered by Shiv Sethi at the Raman Research Institute as part of the RASS summer school and internship program. This one-hour and five-minute lecture is designed for undergraduate and master's students participating in the fully funded 2-week workshop and 8-week research internship focused on astronomy and astrophysics. The RASS program combines expert-led introductory lectures with hands-on research projects, providing students with both theoretical foundations and practical research experience in the field. This session continues building on the fundamental concepts of radiative processes, an essential topic for understanding astronomical phenomena.