﻿ ﻿Answer Key - Nuclear Physics - Homework Helpers: Physics

## 10 Nuclear Physics

The actual answers will be shown in brackets, followed by an explanation. If you don”t understand an explanation that is given in this section, you may want to go back and review the lesson that the question came from.

Lesson 10–1 Review

1. [proton]—A proton is similar in mass to the neutron. Its charge is equal in magnitude to that of an electron.

2. [the nucleus]—The mass of the electrons is not considered significant.

3. [the electron cloud]—The locations of individual electrons are only discussed in terms of probability.

Lesson 10–2 Review

1. [5.38 × 10–20 J]—You may need to look up Planck”s constant (h = 6.63 × 10–34 J × s) and the speed of light in a vacuum (C = 3.00 × 108 m/s). 2. [1.56 × 10–12 m]—You may need to look up the mass of a proton (mp = 1.672 65 × 10–27 kg) and Planck”s constant (h = 6.63 × 10–34 J × s). 3. Lesson 10–3 Review

1. [Mass defect]—The mass defect represents the amount of matter that has been converted into energy.

2. [0.002388 u and 2.22 MeV]—

Given: mp = 1.007 825 u mn = 1.008 665 u 3. [the strong nuclear force]—The strong nuclear force is one of the elemental forces of nature, along with gravity, electromagnetism, and the weak force. The strong force holds the subatomic particles of the nucleus together.

Lesson 10–4 Review

1. [nuclear fusion]—

2. —This is an example of alpha decay. You might need to look up the atomic number of our unknown element on the periodic table to discover its identity. The balanced equation for this reaction is 3. —This is an example of beta-minus decay. The balanced equation is Chapter 10 Examination

1. [e. nucleon]—The number of nucleons in a nucleus is equal to the mass number of the atom.

2. [a. proton]—The number of protons in a nucleus is equal to the atomic number of the atom.

3. [i. positron]—A positron is ejected from a nucleus during beta-plus decay.

4. [k. nuclear fission]—During this process, binding energy is released.

5. [g. atomic number]—It is the atomic number of an element that gives it its identity.

6. [j. beta-minus particle]—During beta-minus decay, the atomic number of the parent isotope will increase by one.

8. [l. nuclear fusion]—Scientists use fusion to produce “new” isotopes.

9. [h. photon]—The energy of a particular photon can be determined using Planck”s constant.

10. [f. quarks]—Quarks are thought to be sub-subatomic particles.

11. [1.39 × 10-40 J ]—Given: f = 2.10 × 10-7Hz h = 6.63 × 10-34 J · s

Find: E 12. [4.83 × 10-18 J ]—

Given: λ = 4.12 × 10-8 m h = 6.63 × 10-34 J · s C = 3.00 × 108 m/s

Find: E 13. [ 2.40 × 10-28 kg · m/s

Given: λ = 2.76 × 10-6 m h = 6.63 × 10-34 J · s

Find: p 14. [ 2.31 × 10-11 m]—

Given: m = 9.109 × 10-31 kg v = 3.15 × 107 m/s

h = 6.63 × 10-34 J · s

Find: λ 15. ﻿