Final answer:
Niels Bohr is often referenced as a key figure in modern physics due to his substantial contributions to the field of quantum mechanics and understanding of atomic structure.
Step-by-step explanation:
The person who is often referred to as the "father of modern physics" is a title that can be attributed to several key figures in history due to their significant contributions. However, when looking at the development of modern physics, especially in terms of quantum mechanics, Niels Bohr is a notable figure. While John Dalton is known as the father of modern atomic theory, Niels Bohr's fundamental contributions to the development of quantum mechanics, a critical part of modern physics, solidify his standing as a pivotal figure in the field. Bohr made use of Ernest Rutherford's planetary model to publish his theory on the hydrogen atom, which greatly advanced the understanding of atomic structure and spectra. For these reasons, Niels Bohr would be the most appropriate answer if we are focusing on the development of modern physics specifically related to quantum mechanics.