\(\mathrm{~A}^{3} \mathrm{H}\) nucleus decays with an energy of \(0.01861 \mathrm{MeV} .\) Convert this energy into (a) electron volts; (b) joules.

In physics, different units are used to measure small amounts of energy, especially at the subatomic level. Often, we encounter energies expressed in Mega-electron Volts (MeV) when dealing with nuclear reactions. However, it may be necessary to convert these values into a more familiar unit, namely electron Volts (eV).
To convert from MeV to eV, you can rely on a simple conversion factor:

• 1 Mega-electron Volt (1 MeV) equals 1 million electron Volts (1 eV).

This is because the prefix 'Mega-' means one million or 10^6. Therefore, if you have an energy of 0.01861 MeV, you can convert it to eV by multiplying by 10^6:
\( 0.01861 \text{ MeV} \times 10^6 = 18610 \text{ eV} \)
So, 0.01861 MeV is equivalent to 18610 eV. This step is crucial in simplifying and understanding energy scales, especially in nuclear physics.

While electron Volts (eV) are commonly used in the field of quantum mechanics and nuclear physics, Joules (J) are the standard unit of energy in the International System of Units (SI). Therefore, converting between these two units might be necessary for various applications. The conversion factor for electron Volts to Joules is:

• 1 eV = 1.60218 \times 10^{-19} Joules

This means that one electron Volt contains approximately 1.60218 × 10^-19 Joules of energy. To convert an energy value from eV to Joules (J), you simply multiply the number of eV by this factor.
Given our example with an energy of 18610 eV: \( 18610 \text{ eV} \times 1.60218 \times 10^{-19} \text{ J/eV} = 2.9807 \times 10^{-15} \text{ J} \)
So, 18610 eV is equivalent to approximately 2.9807 × 10^-15 Joules. This conversion is essential when you need to align nuclear energy values with the broader context of physical energy units.

Energy conversion plays a critical role across various scientific fields. Understanding how to convert energy units is especially vital in nuclear physics, where energies are often expressed in units like electron Volts (eV) and Mega-electron Volts (MeV).
Key Points to Remember:

• Mega-electron Volts to electron Volts: 1 MeV = 10^6 eV.
• electron Volts to Joules: 1 eV = 1.60218 × 10^-19 J.

These conversions are not just academic exercises but have real-world applications. For instance, when studying the energy released by radioactive decay, recognizing these energy equivalents allows scientists to predict and measure phenomena occurring at atomic and subatomic scales.
In summary, having a strong grasp of energy units and their conversions aids in the accurate interpretation of experimental results and the application of nuclear physics principles in technology and medicine.