I looked at the NCERT Physics syllabus of XI and XII. Page on ncert.nic.in
To put it simply:
Mechanical Engineering is an extension of class XI syllabus. You learn about mechanical things such as machines, thermodynamics, engines, cars, design, etc.
Electrical Engineering is an extension of class XII syllabus: Here you learn about electrical stuff such as power distribution and generation, electric motors, transformers, communications (such as wifi, cellphone, etc.), radio, antennas, computer processors, digital systems, transistors, amplifiers, etc.