Which scientist published several groundbreaking papers in 1905, including explanations of special relativity, the equivalence of mass and energy, and the photoelectric effect?

• A. Isaac Newton
• B. Niels Bohr
• C. Albert Einstein
• D. Marie Curie

Answer: (C)

The idea being tested is identifying the scientist behind several landmark 1905 papers, including special relativity, mass–energy equivalence, and the explanation of the photoelectric effect. In 1905, Albert Einstein published work that reshaped physics: the theory of special relativity showed how measurements of space and time depend on the observer’s motion, leading to the famous relation between mass and energy, E = mc^2. He also proposed that light can be thought of as consisting of discrete packets of energy called photons, which explained why electrons are ejected from materials only when light has enough energy, and why the effect depends on light frequency rather than just intensity. These ideas marked a turning point, bridging relativity and quantum concepts and earning Einstein a place as one of the most influential thinkers in science. The other scientists listed made important contributions in different areas or times, but not these specific 1905 papers.