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# Mid-Term Test Example

Due to file conversion, the subscripts, superscripts, and special symbols may not have been adjusted properly. No answer is or will be privided so that you have to work out the answers yourself.

These are some example questions for a midterm test a few years ago. I hope this is helpful for you in your preparation for the final examination.

1. The SI unit (Système International d'Unités) for energy is joule (J). Which one of the following items has the energy closest to one joule?
1. the amount of energy to raise the temperature of 1.0 gram of water by 1.0 K.
2. kinetic energy of an electron being accelerated by a potential of 100 volt.
3. heat produced by burning one gram of gasoline.
4. energy of a photon in the X-ray region with a wavelength of 10-12 m.
5. work of lifting 100 g (0.1 kg) mass up a distance of one meter.

2. Regarding the theory of relativity developed by Einstein in 1905, which one of the following statements is not true?
1. Einstein assumed that light always travels at a constant speed in vacuum of 299,792,458 or 3*108 m/s.
2. The relative mass m is always larger than the rest mass mo of any particle.
3. No particle or object can travel at a speed equal or greater than that of light.
4. Energy released in a chemical explosion is proportional to the difference between the mass of all reactants and the mass of all products.
5. The gain in kinetic energy by a particle can be achieved by losing its mass.

3. Which one of the following is inconsistent with the law of conservation of energy?
1. In a uniform accelerating field, an object which acquires a velocity in its descent can rise exactly as high as it falls if the direction of the velocity is reversed.
2. A liquid flowing out of the basal orifice of a vessel cannot, by virture of its velocity at the efflux, ascend to a greater height than its level in the vessel.
3. When heat is converted to mechanical work, a certain quantity of heat passes from a warmer to a colder body. This quantity of heat is not converted to useful work.
4. Energy converts among various forms without any loss or gain.
5. Rubbing hands together creates heat, because the hands feel warm after a while.

4. Which one of the following is not equal to 1 MeV?
1. The kinetic energy of an electron after it is accelerated by a potential of 1,000,000 volts.
2. The kinetic energy of a proton after it is accelerated by a potential of 1,000,000 volts.
3. The amount of energy equal to 1.602*10-13 N m.
4. The mass slightly less than the sum of the mass of two electrons.
5. The kinetic energy of the C6+ ion after it is accelerated by 1,000,000 volts

5. Choose the best statement that describes the term and concept of chemical element.
1. A pure substance.
2. A substance made up of only one type of nuclide.
3. A substance that consists of only one type of molecule.
4. The simplest form of a substance.
5. A substance that cannot be chemically decomposed into anything simpler.

6. Which one of the following is true?
1. All chemical elements with atomic number less than 92 have been discovered and identified before the periodic table of elements was proposed.
2. Mendeleyev arranged the chemical elements according to the atomic number in the periodic table of elements.
3. The element uranium (U) has not been discovered at the time when Mendeleyev's proposed the periodic tables of element.
4. Mendeleyev produced the periodic table that is hanging in our classroom, Phys.145.
5. Mendeleyev made a bigger impact because he used his periodic table to predict the existence of some unknown elements.

7. Which one of the following is not true?
1. An object containing an excess number of electrons carries a negative charge.
2. The force of attraction between two point charges is proportional to the product of the two charges.
3. When two different metals are placed in a salt solution, there is a tendency of electrons to flow from one metal to another.
4. The electric nature of chemical affinity is due to the tendency of electrons to flow between molecules.
5. The force of attraction between two point charges is inversely proportional to the distance of their separation.

8. An experiment shows that 96485.309 C is required to deposit one mole of silver (Ag) on the electrode. Atomic weight of silver is 108.0. An electrolysis experiment of silver nitrate AgNO3 solution deposited 1.08 g of silver in 2116 seconds. What is the current used in the electrolysis?
1. 9.64 A
2. 4.56 A
3. 0.964 A
4. 0.607 A
5. 0.456 A

9. An electron and a positron annihilate to produce two photons. The rest mass of an electron is 9.1093897*10-31 kg. Calculate the energy of the photon produced in the annihilation.
1. 9.109*10-31 J
2. 2.732*10-22 J
3. 8.187*10-22 J
4. 8.187*10-18 J
5. 8.187*10-14 J

10. The wavelength l of the Balmer series in the hydrogen spectrum is represented by his formula l = 364.56(n2/(n2 - 22)) nm. What is the shortest wavelength (with 3 significant figures) of the series?
1. 656 nm
2. 468 nm
3. 434 nm
4. 91.1 nm
5. 364 nm

11. Regarding the characteristic X-rays of metals and Moseley's law, which one of the following is not true?
1. Moseley discovered a law of nature for the characteristic X-rays of metals.
2. The law provided evidence for a substance as a chemical element.
3. Moseley's law can be applied to predict the existence of an element that has not been discovered.
4. Moseley's law showed that the atomic weights were not reliable for ordering elements.
5. Moseley's law showed that there are Z protons in the atomic nuclei of a metal.

12. The density of potassium bromide, KBr, is 2.75 g/cm3 and it has the same structure as NaCl. A cubic unit cell consists of 4 K+ and 4 Br- ions. The atomic weights of K and Br are 39.1 and 79.9 respectively. Calculate the edge length of the unit cell a. (I have not talked about this type of calculation in the term of 2000 yet).
1. 0.702 nm
2. 0.564 nm
3. 0.354 nm
4. 0.416 nm
5. 0.660 nm

13. What was the material that emitted the radioactive rays discovered by H. Becquerel?
1. Fluorescence material zinc sulfide.
2. Photographic emulsions.
3. A plutonium salt.
4. A thorium salt.
5. Potassium uranyl sulfate, K2UO2(SO4)2.2H2O

14. Regarding the alpha particle scattering experiment performed by Rutherford and his students Hans Geiger and Ernest Marsden, which one of the following is not true?
1. The paths of alpha particles from a source have almost identical length.
2. Most alpha particles pass through the gold foils with no deflection.
3. A very small fraction of the alpha particles are deflected at large angles.
4. When the path of alpha particles is blocked by a thin layer of mica, they noticed some differences in their observations of the a particles.
5. They concluded that the volume of the atom is 100,000 times that of the nucleus and that nearly all the atomic mass is concentrated in the nucleus.

15. The half life of 222Rn86 is 3.823 days. It has the longest half life of all radon isotopes. Calculate the disintegration rate of 1.0 g of radon gas.
1. 4.98*1014 Bq
2. 3.03*1013 Bq
3. 8.18*1012 Bq
4. 1.37*1021 Bq
5. 5.69*1015 Bq

16. Through a series of alpha, beta and gamma decays, 222Rn eventually become a stable nuclide. Which one of the following is that stable nuclide?
1. 208Pb
2. 207Pb
3. 209Bi
4. 204Pb
5. 206Pb

17. The nuclide 254Es99 has a half life of 480 d. If this nuclide undergoes a series of alpha, beta and gamma decays and become the nuclide 238U, how many alpha, and beta particles have to be emitted?
1. 6 alpha and 1 bete particles
2. 5 alpha and 2 bete particles
3. 4 alpha and 3 bete particles
4. 4 alpha and 4 bete particles
5. 4 alpha and 1 bete particles

18. The isotope 14C of carbon is present in small quantities with other isotopes of carbon. It has a half life of 5730 y. A 1.00 gram sample of carbon gives off 15 disintegrations per second. Calculate the number of 14C atoms in this sample?
1. 5.02*1022
2. 4.30*1022
3. 1.82*1012
4. 3.91*1011
5. 3.91*1012

19. Leptons and quarks are the fundamental particles in the standard model. Which list of the following are the leptons of first generation?
1. Electrons, positrons, muons (m+, m-) and muonneutrinos (nm, nm- ).
2. Muons (m+, m- ), and muon neutrinos (nm, nm- ).
3. Up and down quarks
4. Taus (t+, t-) and tau neutrinos (nt, nt- ).
5. Electrons, positrons, electron neutrinos, and anti-electron-neutrinos.

20. What are mesons?
1. Mesons are particles made up of two or more leptons.
2. Mesons are any particles heavier than electrons.
3. Mesons are particles made up of three or more quarks.
4. Mesons are particles with zero charges.
5. Mesons are particles made up of a quark and an antiquark.

I do not intend to provide answers to this example term test. If you have difficulty with a particular question, please e-mail me.

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