The concept of Educational technology has been developed during the last few years. Educational Technology has given a significant contribution in education by taking into consideration the individual differences of the learners and catering to their needs. The emerging trend all over the world is towards more individualized and flexible forms of learning with an emphasison the individualized methods of instructions. This paper has laid a special emphasis on using computers in the teaching and learning process specially for providing instructions in the classroom situations. It is an experimental work to study the effect of Computer Assisted Instruction (CAI) and Traditional Method in teaching Physics at Higher Secondary level. The experiment was carried out on the students of class XI having Physics as one of their subjects of a higher secondary school. Pretest-Posttest equivalent group design is used. Results of the experiment showed that CAI is effective in terms of the achievement of learner in teaching Physics at Posttest stage.