In modern physics, which scientist clearly stated and formulated the principle that matter can be converted into energy and energy into matter?

Introduction / Context:
One of the most famous ideas in modern physics is that matter and energy are interchangeable, captured in the equation E = m * c^2. This relation shows that a small amount of mass can be converted into a large amount of energy and vice versa. The question asks which scientist is associated with clearly stating and formulating this principle in the form of a precise theory, which is a well-known fact in general science and competitive exams.

Given Data / Assumptions:
- The principle in question is the equivalence of mass and energy: matter can be converted into energy. - Scientists listed include Boyle, Lavoisier, Avogadro, and Einstein. - We assume standard historical attributions from physics and chemistry. - We must connect the principle with the correct scientist.

Concept / Approach:
Albert Einstein, through his special theory of relativity, derived the mass-energy equivalence formula E = m * c^2, where E is energy, m is mass, and c is the speed of light in vacuum. This formula mathematically expresses the possibility of converting matter into energy and explains phenomena like nuclear reactions. Boyle is associated with gas laws, Lavoisier with the law of conservation of mass in chemical reactions, and Avogadro with the concept of the mole and volume relationships of gases. The correct approach is to link the concept of mass-energy equivalence to Einstein.

Step-by-Step Solution:
Step 1: Recall that Albert Einstein developed the special theory of relativity in 1905, which led to the equation E = m * c^2. Step 2: Understand that this equation means mass can be viewed as a form of energy; thus matter can be converted into energy. Step 3: Recognise that Robert Boyle is best known for Boyle's law relating pressure and volume of a gas, not for mass-energy equivalence. Step 4: Recognise that Antoine Lavoisier established the law of conservation of mass in chemical reactions, stating that mass is conserved, but did not introduce mass-energy equivalence. Step 5: Recognise that Amedeo Avogadro proposed Avogadro's hypothesis about equal volumes of gases containing equal numbers of molecules, which is unrelated to matter-energy conversion. Step 6: Therefore, only Albert Einstein matches the principle that matter can be converted into energy and vice versa.

Verification / Alternative check:
Physics textbooks and even general knowledge sources frequently mention Einstein's equation E = m * c^2 as one of the most famous scientific formulae in history. It is used to explain the enormous energy released in nuclear fission and fusion reactions and underlies the working of atomic and hydrogen bombs. These applications are direct examples of matter being converted into energy. No other scientist among the options is credited with this specific theoretical insight, which confirms Einstein as the correct answer.

Why Other Options Are Wrong:
Boyle's work focused on the behaviour of gases under pressure and temperature changes, not on the equivalence of mass and energy. Lavoisier emphasised that mass is conserved in chemical reactions, which is approximately true in chemical processes where mass changes are extremely small; he did not propose that mass could be transformed into energy. Avogadro dealt with gas volumes and particle numbers, providing the foundation for the mole concept. None of these contributions involve the mass-energy conversion principle described in the question.

Common Pitfalls:
Some students may confuse Lavoisier's conservation of mass with Einstein's mass-energy equivalence. While both deal with mass, they address different aspects: conservation of mass in chemical reactions versus convertibility of mass and energy in nuclear and relativistic contexts. Another pitfall is simply guessing based on familiarity with names. To avoid mistakes, remember that whenever you see E = m * c^2 or the idea of matter converting to energy, you should immediately think of Albert Einstein.

Final Answer:
The scientist who clearly stated that matter can be converted into energy is Albert Einstein.