Which statement correctly states the electron's mass relative to the proton?

Which statement correctly states the electron's mass relative to the proton?

• A. 1/1832 amu
• B. 1 amu
• C. 1832 amu
• D. 2 amu

Answer: (D)

The main idea is that the electron is by far lighter than the proton. In numbers, the electron’s mass is about 9.11×10^-31 kg while the proton’s mass is about 1.67×10^-27 kg, giving a ratio of roughly 5.45×10^-4, which is about 1/1836. In atomic mass units, the proton is defined as 1 amu and the electron is about 0.00055 amu, so the electron’s mass relative to the proton is about 1/1836. Among the options, the statement that expresses a tiny fraction like about 1/1832 amu best matches this reality; the other options imply masses around 1 amu or larger, which would be far too large for an electron.

The main idea is that the electron is by far lighter than the proton. In numbers, the electron’s mass is about 9.11×10^-31 kg while the proton’s mass is about 1.67×10^-27 kg, giving a ratio of roughly 5.45×10^-4, which is about 1/1836. In atomic mass units, the proton is defined as 1 amu and the electron is about 0.00055 amu, so the electron’s mass relative to the proton is about 1/1836. Among the options, the statement that expresses a tiny fraction like about 1/1832 amu best matches this reality; the other options imply masses around 1 amu or larger, which would be far too large for an electron.