The major goal of biophysics is to understand how living systems work in terms of physical mechanisms. For example, the study of electricity is the domain of the physicist. The biophysicist is interested in electric current flow in living material, especially in such tissues as nerve and muscle which generate electrical signals.
Electromagnetic radiation is an area of interest to the physicist.
The interaction between electromagnetic radiation and living matter is an area of biophysics. And so on. Bioengineering , on the other hand, is defined as much by its techniques as its goals. Computerized analysis of visual images of living systems is a good example, as are ultrasonic techniques for looking inside living structures. Both biophysicists and bioengineers must be good at, and enjoy, the quantitative sciences such as physics and chemistry, and should also be at least fairly strong in mathematics.