1. A knight on horseback holds a 10-m lance. The horse can run at 0.70 c. (It wins most of its races!) How long will the lance appear to a person that is standing still on the ground as the horse runs past?

a.7.1 m

b.10 m

c.14 m

d.15 m

e.21 m

Ans. A

2. How fast would a rocket have to move past a ground observer if the latter were to observe a 4.0% length shrinkage in the rocket length? (c = 3.00  108 m/s)

a.0.12  108 m/s

b.0.28  108 m/s

c.0.84  108 m/s

d.1.2  108 m/s

e.1.7  108 m/s

Ans. C

3. A proton with mass 1.67  1027 kg moves with a speed of 0.600 c in an accelerator. What is its relativistic momentum? (c = 3.00  108 m/s)

a.0.530  1019 kgm/s

b.2.40  1019 kgm/s

c.3.76  1019 kgm/s

d.6.67  1019 kgm/s

e.8.85  1019 kgm/s

Ans. C

4. The observed relativistic length of a super rocket moving by the observer at 0.70 c will be what factor times that of the measured rocket length if it were at rest?

a.0.45

b.0.71

c.0.82

d.1.4

e.1.9

Ans. B

5. A muon formed high in Earth's atmosphere travels at a speed 0.990 0 c for a distance (as we see it) of 4 600 m before it decays. How far does the muon travel as measured in its frame?

a.4 554 m

b.2 596 m

c.1 298 m

d.649 m

e.427 m

Ans. D

6. A muon formed high in the Earth's atmosphere travels at a speed 0.990 c for a distance of 4.60 km before it decays. What is the muon's lifetime as measured in its reference frame?

a.1.55  105 s

b.2.18  106 s

c.3.04  106 s

d.4.65  106 s

e.5.77  106 s

Ans. B

7. A star is receding from the Earth at 0.70 c when it emits a burst of material at 0.80 c from its surface in the direction away from the Earth. What is the speed of the burst relative to the Earth?

a.0.96 c

b.1.50 c

c.0.22 c

d.0.88 c

e.0.99 c

Ans. A

8. When a one-megaton nuclear bomb is exploded, approximately 4.5  1015 J of energy is released. How much mass would this represent in a mass-to-energy conversion? (c = 3.00  108 m/s)

a.1.5  106 kg

b.0.050 kg

c.5.3  1010 kg

d.1.7  103 kg

e.4.5  106 kg

Ans. B

9. If a monochromatic light beam with quantum energy value of 3.0 eV incident upon a photocell where the work function of the target metal is 1.60 eV, what is the maximum kinetic energy of ejected electrons?

a.4.6 eV

b.4.8 eV

c.1.4 eV

d.2.4 eV

e.3.8 eV

Ans. C

10. What is the frequency of monochromatic light where the photon energy is 5.5  1019 J? (h = 6.63 1034 Js)

a.2.2  1014 Hz

b.4.4  1014 Hz

c.8.3  1014 Hz

d.9.8  1014 Hz

e.1.4  1015 Hz

Ans. C

11. What is the wavelength of a monochromatic light beam, where the photon energy is 5.00  1019 J? (h = 6.63  1034 Js, c = 3.00  108 m/s, and 1 nm = 109 m)

a.354 nm

b.398 nm

c.414 nm

d.787 nm

e.875 nm

Ans. B

12. What is the de Broglie wavelength for a proton (m = 1.67  1027 kg) moving at a speed of 6.0  106 m/s? (h = 6.63  1034 Js)

a.2.0  1013 m

b.0.33  1013 m

c.1.3 1013 m

d.0.66  1013 m

e.0.23  1013 m

Ans. D

13. Of the various wavelengths emitted from a hydrogen gas discharge tube, those that are associated with transitions from higher levels down to the n = 1 level produce which of the following?

a.infrared

b.visible

c.mixture of infrared and visible

d.ultraviolet

e.x-rays

Ans. D

14. The Lyman series of hydrogen is made up of those transitions made from higher levels to n = 1. If the first line in this series has a wavelength of 122 nm, what is the wavelength of the second line?

a.49 nm

b.103 nm

c.364 nm

d.486 nm

e.632 nm

Ans. B

15. If there are 146 neutrons in 238U, how many neutrons are found in the nucleus of 235U?

a.141

b.143

c.145

d.147

e.149

Ans. B

16. An element is emitting alpha, beta, and gamma radiation. Rank order them in terms of the thickness of protective shielding they will need for safety, from least to most.

a.alpha, beta and gamma

b.gamma, beta and alpha

c.beta, gamma and alpha

d.alpha, gamma and beta

e.beta, alpha and gamma

Ans. A

17. Samples of two different isotopes, X and Y. both contain the same number of radioactive atoms. Sample X has a half-life twice that of Y. How do their decay rates compare?

a.X has a greater rate than Y

b.X has a smaller rate than Y

c.rates of X and Y are equal

d.rate depends on atomic number, not half-life

Ans. B

18. An ancient building was known to have been built 3 000 years ago. Approximately what proportion of Carbon-14 atoms are yet in the building's wooden framing compared to the number which were present at the time of its construction? (half life of 14C = 5 730 years)

a.0.425

b.0.500

c.0.517

d.0.696

e.0.738

Ans. D

19. A pure sample of 226Ra contains 2.0  1014 atoms of the isotope. If the half-life of 226Ra = 1.6  103 years, what is the decay rate of this sample? (1 Ci = 3.7  1010 decays/s)

a.2.7  1012 Ci

b.3.4  1010 Ci

c.7.4  108 Ci

d.9.6  106 Ci

e.2.3  105 Ci

Ans. C

20. When radium-224 emits an alpha particle, the remaining daughter nucleus is which of the following?

a.lead-213

b.actinium-215

c.radon-220

d.bismuth-215

e.polonium-209

Ans. C

21. In the beta decay of 14C, the existence of the antineutrino was required to maintain:

a.energy conservation.

b.charge conservation.

c.conservation of the number of nucleons.

d.all of the above.

e.none of the above.

Ans. A

22. In the four radioactive series, the nuclei decay by either emitting alpha particles or beta particles until they reach the stable end product. Each decay, therefore, results in a mass number change of either 4 (for alpha decay) or 0 (for beta decay). The radium isotope 226Ra is in one of these series. What is the starting isotope in the series containing 226Ra?

a.238U

b.235U

c.232Th

d.237Np

Ans. A

23. In the reaction , what are the mass number and atomic number of the product designated by ?

a.102, 42

b.101, 42

c.102, 44

d.101, 44

e.not given

Ans. A