Final answer:
When hydrogen is fused into helium, energy is released through the conversion of mass to energy. In nuclear fusion reactions, a small fraction of the mass of the hydrogen atoms is converted into energy, resulting in the release of a large amount of energy.
Step-by-step explanation:
When hydrogen is fused into helium, energy is released through the conversion of mass to energy. This is due to the principle of mass-energy equivalence, as described by Einstein's famous equation E = mc^2. In nuclear fusion reactions, a small fraction of the mass of the hydrogen atoms is converted into energy, resulting in the release of a large amount of energy. This energy can be calculated using the equation E = mc^2, where E is the energy released, m is the mass converted, and c is the speed of light.
For example, in the given question, 2 g of hydrogen is converted into 1.985 g of helium. To find the energy released, we can use the equation E = mc^2, where m is the mass converted and c is the speed of light. Substituting the values, we get:
E = (1.985 g) * (3 x 10^8 m/s)^2 = 4.5 x 10^6 J
Therefore, the correct answer is (b) 4.5 x 10^6 J.