Mechanical, Civil & Electrical are the oldest and most common branches. The earlier part of an engineering course is common to all branches with a few exceptions. You are taught a little bit of all the branches and a foundation is built up to carry you through the remaining course.
After the initial phase, which is the first year of a four year course, the branch specialization starts and commonality fades away. Mechanical engineering courses go through the principles, design and usage of mechanisms and machinery. As engineering deals with the real life application of technical knowhow, a mechanical engineering student later learns about functioning and establishment of various projects. Mechanical engineering graduates are sought after in all of the industries where machines are involved. Civil engineering deals with the construction and development requirements of society therefore here you will study how to build houses, bridges, roads etc. The intake for civil engineering is mostly in construction companies and construction departments of government.
Electrical engineering is all about electrical power generation, distribution and usage. An electrical engineer is required wherever electrical equipment are used in industry - be it for generation, transmission, distribution or consumption. Branches which developed later are Chemical, Electronics, Telecommunication, Production, Automobile, Aeronautical, Space, Marine, Instrumentation, Pulp & Paper, Pharmaceutical, Biomedical, Computers, Architectural, Robotics etc. many institutes offer combined branches viz. Electronics & Telecommunication etc in a single course. I recently heard about a branch named Mechanotronics which is a combination of Mechanical & Electronics dealing mostly with Instrumentation & Control. Normally new branches take birth at Masters or Research level. Then as the technique develops and study material is accumulated the same is offered at undergraduate levels. The nomenclatures are quite literal and give a fair idea of what to expect in that branch of engineering. Brief of all the above branches are given below:
CHEMICAL: A highly sought after branch if you wish to work in fertilizer plants, petrochemicals etc. Deals basically with application of chemistry and manufacture of various chemicals at an industrial level. Few institutions offer Petrochemical engineering courses too.
ELECTRONICS: Study of electronic equipment design and usage. Good scope in Consumer goods industry.
TELECOMMUNICATION: Generally offered in combination with Electronics. Great scope now-a-days in the era of receding distances. Telephone companies, Airports, Telecommunication Equipment manufacturer would be your employers.
PRODUCTION: Mechanical engineering modified from purely industrial production point of view.
AUTOMOBILE: Again Mechanical Engineering modified from the design, production and maintenance of automobile machinery.
INDUSTRIAL: Another development of Mechanical Engineering with an industrial point of view. Great stress on techniques to establish and run industrial plants.
AERONAUTICAL: Design and manufacture of aircrafts. Limited scope - in a developing country like India.
SPACE: Again a highly specialized branch but with a limited scope. Teaches you about techniques, machinery and equipment used to explore the space.
MARINE: Marine engineering teaches you to design, use and maintain Boats & Ships. Great scope internationally. Generally a short-career branch as it yields good money but a demanding lifestyle. Ex-Marine engineers are sought after by hotel industry as they are well versed in maintenance of air-conditioning plants, independent power generation and water-waste management.
INSTRUMENTATION: This branch deals with measurement and monitoring of various parameters. It’s a combination Mechanical, Electrical, Electronics and Computers with focus on industrial measurement & control.
COMPUTER SCIENCE: Here you learn all about principles, design and usage of computers. Do not confuse this with Software Engineering degrees offered through programming courses. This course goes much in depth and teaches you a lot more in all the fields related with computers.