1. | \(12\) u | is exact
2. | \(12\) u | is less than
3. | \(12\) u | is more than
4. | depends on the form of carbon such as graphite or charcoal |
The mass number of a nucleus is equal to:
1. | the number of neutrons in the nucleus. |
2. | the number of protons in the nucleus. |
3. | the number of nucleons in the nucleus. |
4. | none of them. |
1. | conservation of charge |
2. | conservation of mass |
3. | conservation of mass-energy |
4. | conservation of momentum |
(a) | nuclear forces have short-range. |
(b) | nuclei are positively charged. |
(c) | the original nuclei must be completely ionized before fusion can take place. |
(d) | the original nuclei must first break up before combining with each other. |
1. | \(4.9 \times 10^{4} \text{ years }\) | 2. | \(2.8 \times 10^{4} \text { years }\) |
3. | \(3.0 \times 10^{4} \text { years }\) | 4. | \(3.9 \times 10^{4} \text { years }\) |