Question

Напишите бета-распад 92 снизу и 239 вверху U. Какое(-ие) утверждение(-я) верно(-ы)? А: масса ядра всегда меньше суммы масс протонов и нейтронов в этом ядре Б: масса ядра всегда равна сумме масс протонов и нейтронов в этом ядре 1) Только А 2) И А, и Б 3) Только Б 4) Ни А, ни Б

Answer 1

1) ²³⁹₉₂U → ²³⁹₉₃Np + ⁰₋₁e⁻
2) • Масса ядра всегда меньше суммы масс протонов и нейтронов.                   Утверждение верно. 
    • Масса ядра всегда равна сумме масс протонов и нейтронов.                       Утверждение верно.
   Ответ: 2

Answer 2

Beta Decay of U-239

Beta decay is a type of radioactive decay in which a beta particle (either an electron or a positron) is emitted from an atomic nucleus. In the case of U-239, beta decay occurs when a neutron in the nucleus is converted into a proton, resulting in the emission of a beta particle.

The statement that is true regarding the beta decay of U-239 is:

1) Only statement A is true: The mass of the nucleus is always less than the sum of the masses of the protons and neutrons in that nucleus.

This statement is supported by the fact that during beta decay, a neutron is converted into a proton. Since a proton has a slightly smaller mass than a neutron, the mass of the nucleus decreases after beta decay.

It is important to note that the mass of the nucleus is not always equal to the sum of the masses of the protons and neutrons in that nucleus. This is because a small amount of mass is converted into energy during the beta decay process, as described by Einstein's famous equation, E=mc².

Therefore, the correct answer is option 1) Only statement A is true: The mass of the nucleus is always less than the sum of the masses of the protons and neutrons in that nucleus.

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