1. What is the approximate mass of a free neutron in atomic mass units?
A.
0.511 u
B.
1.008665 u
C.
1.6726 u
D.
0.000548 u
Correct Answer:
1.008665 u
Explanation:
The mass of a free neutron is approximately 1.008665 atomic mass units (u).
2. What is the approximate mass of a neutron in kilograms?
A.
9.11 × 10^-31 kg
B.
1.67 × 10^-27 kg
C.
1.67 × 10^-30 kg
D.
1.00 × 10^-27 kg
Correct Answer:
1.67 × 10^-27 kg
Explanation:
A neutron has an approximate mass of 1.675 × 10^-27 kg, commonly rounded to 1.67 × 10^-27 kg.
3. Which symbol commonly represents the mass of a neutron?
A.
m_e
B.
m_p
C.
m_n
D.
m_a
Correct Answer:
m_n
Explanation:
The symbol m_n is conventionally used for the mass of a neutron.
4. Compared with the mass of a proton, the mass of a neutron is approximately:
A.
Slightly greater
B.
Exactly zero
C.
Slightly smaller
D.
About half as large
Correct Answer:
Slightly greater
Explanation:
The neutron mass is slightly greater than the proton mass. The neutron is about 1.008665 u, while the proton is about 1.007276 u.
5. Which value is most suitable for the neutron mass in a basic nuclear-mass calculation?
A.
0.000548 u
B.
1.008665 u
C.
0.511 u
D.
938.3 u
Correct Answer:
1.008665 u
Explanation:
For nuclear calculations, the neutron mass is commonly taken as 1.008665 u.
6. A neutron has no electric charge. Which statement about its mass is correct?
A.
Its mass is zero because its charge is zero
B.
Its mass is approximately 1.008665 u
C.
Its mass is equal to the electron mass
D.
Its mass is less than one-thousandth of a proton mass
Correct Answer:
Its mass is approximately 1.008665 u
Explanation:
Although a neutron is electrically neutral, it has a substantial mass of approximately 1.008665 u.
7. The rest mass of a neutron is closest to which energy equivalent?
A.
0.511 MeV
B.
1.008 MeV
C.
939.6 MeV
D.
1836 MeV
Correct Answer:
939.6 MeV
Explanation:
Using E = mc², the neutron rest mass corresponds to approximately 939.6 MeV.
8. Which particle has a mass approximately equal to 1.008665 u?
A.
Electron
B.
Photon
C.
Neutron
D.
Alpha particle
Correct Answer:
Neutron
Explanation:
The mass value 1.008665 u is the standard approximate mass of a free neutron.
9. If the neutron mass is written as 1.008665 u, what does the unit u represent?
A.
Unified atomic mass unit
B.
Unit of electric charge
C.
Unit of nuclear radius
D.
Unit of energy only
Correct Answer:
Unified atomic mass unit
Explanation:
The symbol u denotes the unified atomic mass unit, which is commonly used to express neutron mass.
10. Which approximate mass should be used for a neutron when no greater precision is required?
A.
1 u
B.
0.5 u
C.
0.001 u
D.
2 u
Correct Answer:
1 u
Explanation:
For simple estimates, the neutron mass is approximated as 1 u because its precise value is 1.008665 u.
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