Fill in the missing particles o lu c1y)u5+efmr nuclei:
(a) $\text{n} + _{56}^{137}\text{Ba} \to ? + \gamma$
(b) $\text{n} + _{55}^{137}\text{Cs} \to _{56}^{137}\text{Ba} + 2?$
(c) $_{92}^{235}\text{U} + \text{n} \to _{38}^{90}\text{Sr} + ? + 3\text{n}$
(d) $? + \text{d} \to _{79}^{197}\text{Au} + \alpha$
where d stands for deuterium ($_{1}^{2}\text{H}$).

The isotope $_{15}^{32}\text{P}$ is produced by the reaction: $? + \text{n} \to _{15}^{32}\text{P} + \text{p}$. What must be the target nucleus?

When $_{11}^{22}\text{Na}$ is bombarded by deuterons ($_{1}^{2}\text{H}$), an $\alpha$ particle is emitted. What is the resulting nuclide?

Why are neutrons such7uinbj7f/exvi:uf;71 hz4 2p rm:vd6 dsvx -g good projectiles for producing nuclear reactions?

A proton strikes a $_{10}^{20}\text{Ne}$ nucleus, and an $\alpha$ particle is observed to emerge. What is the residual nucleus? Write down the reaction equation.

Are fission fragments ,4t(bpqqxa; m $\beta^+$ or $\beta^-$ emitters? Explain.

  If $_{92}^{235}\text{U}$ released only 1.5 neutrons per fission on the average, would a chain reaction be possible?  ----待选择----yesno 
If so, what would be different?

$_{94}^{238}\text{Pu}$ releases an average of 2.5 neutrons per fission compared to 2.9 for $_{94}^{239}\text{Pu}$. Pure samples of which of these two nuclei do you think would have the smaller critical mass? Explain.

The energy from nuclear fission appears in the form of thermal energy - tr0;6h23 oorq2vyx c rbut the thermal energy ofyvh ;2t q02oc rr36rxo what?

The energy from nuclear fission appears in the form of thermal en(.fr .g ehqd*tvm7s y-ergy - but the thermal enerf*esvqt.d (m .-ghyr 7gy of what?

Why can't uranium be ;rq asi,zke.q*(7gxsenriched by chemical means?

How can a neutron, with practically no kinetic energy, 0aiy5zm p c 5/0ki.kg m9jhmp7excite a nucleus to the extent showy/m hj p.mza 5059imk p0ikg7cn in (Fig. Below)?

Why would a porous block of urani 1z jkh)/yq.znum be more likely to explode if kept under water rather than1y n)hk. /zqjz in air?

A reactor that uses highly enriched uranium can use ordinary6a ;jium tzkng23 3,pv water (instead of heavy water) as a moderator and still have a self-,zunm6t3i pk ja 23v;gsustaining chain reaction. Explain.

Why must the fission process release neutrons if it is to be u dvht.rxh3rncri1o o;p pey :hj8 -*9:seful?

Discuss the relative merits and disadvantages, including pollution and safeujz 3i57cbe zf-r-9cv ty, of power generation by fossil fuelc59-z i-efvu jrzb7 c3s, nuclear fission, and nuclear fusion.

What is the reason for the "secondary system"m0jo 0pl eu+4s in a nuclear reactor, (Fig. Below)? That is, why is the water heated by t+ lu0j p4s0omehe fuel in a nuclear reactor not used directly to drive the turbines?

Why are neutrons released in a fission reavh;c+whvt 3e+akr)5 q0xp/ oyction?

Why do gamma particles penetrate matter more easily than beta particles doqrwu;w11 un*p?

A higher temperature is required for deuterium-deuterium igs(rem tcz) a,w 6-jj,znition than for deuterium-tritium. Explasj6(erwz t-am j),,cz in.

Light energy emitted by the Sun and stars comes from the fusion qc(m,ra8c9+ ye3 bm viprocess. What conditions in the interiyb mma c8qcr9e+(, iv3or of stars make this possible?

How do stars, and our Sun, maintain confinement of the plasma for fusid j n(ievou9tnyz+o,.1c a* j3on?

What is the basic difference vov km izria7 6-p+ldzx,-v 4ht/;t g;between fission and fusion?

People who work around metals that emit alpha pyj7wyu1 g88yt -yd* w2 np vwva:yjh:)articles are trained that there is little danger from proximity or even touchiny*: j-2y7vvy1yju8dgp:8 )ay n wh wwtg the material, but that they must take extreme precautions against ingesting it. Hence, there are strong rules against eating and drinking while working, and against machining the metal. Why?

Why is the recommended maximum rar yin )2 /(wj0i8pwwnxdiation dose higher for women beyond the child-bea0i n) wiwrn/wy8jx (2pring age than for younger women?

Radiation is sometimes used to sterilize medical supplies t.s mh.qzh8f vg5;lm ,and even food. Explain how it works.tlvg5h h. ,;mmf.qs z8

What is the difference between absorbed dose ani2g 6 ta ,andqsh26t,ad effective dose? What are the SI units for 6q2 sntah,a,t6dag 2 ieach?

How might radioactive troatb+87bea0)lba kuhw9 k. l ,acers be used to find a leak in a pipe?

Natural aluminum is cx1m8(3 jpebcfu drzcn 1+t42 all $_{13}^{27}\text{Al}$. If it absorbs a neutron, what does it become? Does it decay by $\beta^-$ or $\beta^+$? What will be the product nucleus?

Determine whether the reac t k 8:z11v.mwwerdkk5l: 2eutiqq)w/ tion $_{1}^{2}\text{H} + _{1}^{2}\text{H} \to _{2}^{3}\text{He} + \text{n}$ requires a threshold energy.

Is the reaction $\text{n} + _{92}^{238}\text{U} \to _{92}^{239}\text{U} + \gamma$ possible with slow neutrons? Explain.

  Does the reaction $_{3}^{7}\text{Li} + \text{p} \to _{2}^{4}\text{He} + \alpha$ require energy, or does it release energy? How much energy?    MeV

  Calculate the energy relea en7/y wmzo7t,sed (or energy input required) for the reaction $_{5}^{10}\text{B} + \text{p} \to _{3}^{7}\text{Li} + \alpha$.    MeV

  (a) Can the reaction i k/be6s;zoo5 $_{11}^{23}\text{Na} + \text{d} \to \text{n} + _{12}^{24}\text{Mg}$ occur if the bombarding particles have 10.00 MeV of kinetic energy? (d stands for deuterium, $_{1}^{2}\text{H}$)
(b) If so, how much energy is released?    MeV

  (a) Can the reaction.qs28 f)0aw-.z eup dz8nsw8xzf m zh(sc(3ak $_{3}^{7}\text{Li} + \text{p} \to _{2}^{4}\text{He} + \alpha$ occur if the incident proton has kinetic energy = 2500 keV?
(b) If so, what is the total kinetic energy of the products?    MeV

  In the reaction $_{8}^{18}\text{O} + \text{p} \to _{9}^{18}\text{F} + \gamma$, the incident $\alpha$ particles have 7.68 MeV of kinetic energy.
(a) Can this reaction occur?
(b) If so, what is the total kinetic energy of the products? The mass of $_{9}^{18}\text{F}$ is 16.999131 u.   MeV

  Calculate the Q-value for the "capture"imeg+y99t/4 r-ps pqmug0x b1 reaction $_{2}^{4}\text{He} + _{4}^{9}\text{Be} \to _{6}^{12}\text{C} + \text{n}$. Q =    MeV

  Calculate the total kinetic energy of zhaanf(f((8 d9i5s t ehu8.tl b4ed1v a. o+pqthe products of the reaction $_{6}^{12}\text{C} + \text{d} \to _{7}^{13}\text{N} + \text{p}$ if the incoming deuteron (d) has $KE = 36.3\ \text{MeV}$. $KE_{\text{total}}$ =    MeV

  Radioactive $_{6}^{14}\text{C}$ is produced in the atmosphere when a neutron is absorbed by $_{7}^{14}\text{N}$. Write the reaction and find its Q-value. Q =    MeV

  An example of a "stripping" nuclear reaction is 8-v cwa5rwtiby gu5m7 f05h8v$\text{d} + _{3}^{7}\text{Li} \to \text{X} + \text{p}$.
(a) What is X, the resulting nucleus?
(b) Why is it called a "stripping" reaction?
(c) What is the Q-value of this reaction? Is the reaction endothermic or exothermic? Q =    MeV

  An example of a "pick-up" nuclear reactiwtmahj)/lr:v1s1rgyf r5 s6s w r:k2 +on is $_{1}^{2}\text{H} + _{6}^{12}\text{C} \to \text{X} + \alpha$.
(a) Why is it called a "pickup" reaction?
(b) What is the resulting nucleus?
(c) What is the Q-value of this reaction? Is the reaction endothermic or exothermic?Q =    MeV

  (a) Complete the following nuclear rdai t;f:/hs(x6 u +tpeeaction: $\text{p} + ? \to _{16}^{32}\text{S} + \gamma$.
(b) What is the Q-value? Q =    MeV

  The reaction $_{9}^{19}\text{F} + \text{n} \to _{9}^{20}\text{F} + \gamma$ requires an input of energy equal to 2.453 MeV. What is the mass of $_{9}^{20}\text{F}$?
$m_{^{18}_{9}F}$ =    U

  Calculate the energy released in the fzn; wb-kx((e*fto3mlku 6 o1 sission reaction $_{92}^{235}\text{U} + \text{n} \to _{56}^{141}\text{Ba} + _{36}^{92}\text{Kr} + 3\text{n}$. Use Appendix B, and assume the initial kinetic energy of the neutron is very small. Q =    MeV

  What is the energy released in the fiss*5 bl.-jyp6hsan- ejj anif /5ion reaction of Eq. 31-4? (The masses of f.hjbns yin5l*5 p6e--j/aaj$_{56}^{140}\text{Ba}$ and $_{36}^{92}\text{Kr}$ are 140.914411 u and 91.926156 u, respectively.) Q =    MeV

  How many fissions take place;lys8 0qzntc x :y82oe per second in a 200-MW reactor? Assume 200 MeV is releasee8t xyzlsn: 02coy;8 qd per fission. P =    $\times 10^{13}\ \text{reactions/s}$

  The energy produced by a fission reactor is about 200 MeV per fission. Wl6ymltd e2s 7m9j(mfx4bww * ,g)lxj2 hat fraction of the rest mass of al2mlf,w 7xbmt6 emwl4(xj *9g)2sjdy $_{92}^{235}\text{U}$ nucleus is this? The ratio is about $\approx 1 : $   

  Consider the fission reactioalxs- hl l+ xx**a1eg3n $_{92}^{235}\text{U} + \text{n} \to _{51}^{133}\text{Sb} + _{41}^{98}\text{Nb} + ?\text{n}$.
(a) How many neutrons are produced in this reaction?   
(b) Calculate the energy release. The atomic masses for Sb and Nb isotopes are 132.915250 u and 97.910328 u, respectively. Q =    MeV

  How much mass of $_{92}^{235}\text{U}$ is required to produce the same amount of energy as burning 1.0 kg of coal (about $3 \times 10^7\ \text{J}$)?    $ \times 10^{-7}\ \text{kg}$

  Suppose that the electric average power consumption, day ane f+ (brao.5gsjt;y b3d night, in a typical hous;og+e( jyf ab5b3.t rse is 950 W. What initial mass of $_{92}^{235}\text{U}$ would have to undergo fission to supply the electrical needs of such a house for a year? (Assume 200 MeV is released per fission, as well as 100% efficiency.)    $ \times 10^{-4}\ \text{kg}$

  What initial mass of mzbx0xa8-weuc0m- 3c $_{92}^{235}\text{U}$ is required to operate a 650-MW reactor for 1 yr? Assume 40% efficiency. The initial mass is $\approx $    $\ \text{kg}$

  Assuming a fission om yg0f:a db,.fn )/lncf $_{92}^{235}\text{U}$ into two roughly equal fragments, estimate the electric potential energy just as the fragments separate from each other. Assume that the fragments are spherical (see Eq. 30-1) and compare your calculation to the nuclear fission energy released, about 200 MeV.
PE =    MeV
This is about    % larger than the nuclear fission energy released.

  What is the average kinetic energy of protons at the center of :q6( hrvo yj,ra star where the temperah ,qorv6yr(j:ture is $2 \times 10^7\ \text{K}$?
KE =    $ \times 10^{-16}\ \text{J}$
KE =    eV

  Calculate the energy released in thes8 +rj+cl *lu6 9ltnrz.u / rj)gpmw5i fusion reaction $_{1}^{2}\text{H} + _{1}^{3}\text{H} \to _{2}^{4}\text{He} + \text{n}$ is    MeV.

  Calculate the energy rfoaub3ymebzn 7623 9 j (ae;nneleased when two deuterium nuclei fuse to form $_{2}^{3}\text{He}$ with the release of a neutron is    MeV.

  Verify the Q-value statew1yegc,p o0 ,b-5qtecd for each of the reactions ofEqs. 31-6.
Eqs. 31-6-a Q =    MeV
Eqs. 31-6-b Q =    MeV
Eqs. 31-6-c Q =    MeV

  Calculate the energy release per gram of fuel for the reactions of Eqs. 31-8ar l )vi.v2utuu+ (y7sq, b, and c. Compare to the energy release per gram of uranium .+tyuvu u(lvq2i sr)7in fission.
31-8a =    $ \times 10^{23}\ \text{MeV/g}$
31-8b =    $\times 10^{23}\ \text{MeV/g}$
31-8c =    $ \times 10^{24}\ \text{MeV/g}$
Uranium fission =    $ \times 10^{23}\ \text{MeV/g}$

  How much energy is released whesr2ke//+w fxa9 ;wv,j*z9twkcc*b xu n $_{92}^{238}\text{U}$ absorbs a slow neutron ($KE \approx 0$) and becomes $_{92}^{239}\text{U}$? Q =    MeV

  If a typical house requires 950 W of electric power on average, what mi1 tlnuogbit2qlyq6i4 q5 3+0nw9p a-enimum amount of deuterium fuelt1qe05t ib62gnpq-9i3nwa4 + ll q you would have to be used in a year to supply these electrical needs? Assume the reaction of Eq.31- 8b.    g

Show that the energies carried off by the g ui6*n;5a w8yp c6jty(w0l sh$_{2}^{4}\text{He}$ nucleus and the neutron for the reaction of Eq. 31-8c are about 3.5 MeV and 14 MeV, respectively. Are these fixed values, independent of the plasma temperature?

  Suppose a fusion reactor ran on "d-d" reactions, Eqs. 31-8a and b. Estimn 06k)u4 ucecl) blf-iate how much water, for fuel, would be 0 4)ecc- ni)fl6ulbukneeded per hour to run a 1000-MW reactor, assuming 30% efficiency. $\approx$    $kg/h$

  How much energy (J) isvh5i1 01i/r w:gwlnxu *m6g ot contained in 1.00 kg of water if its natural deuterium is used in the fusion reaction of Eq. 31-8a? Compare to the energy obtained from the burninm r:tvigwu 15/gxw6 0i1* onhlg of 1.0 kg of gasoline, about $5 \times 10^7\ \text{J}$.
   $ \times 10^{9}\ \text{J}$
   times more than gasoline

The energy output of massive stars is belaoagtwh r4pi+ -0x0 pn0u 432udz/iaxri: v v3ieved to be due to the carbon cycle (see text). (a) Show that no carbon is consumed in this cycle and that the net effect is the same as for the proton-proton cycle. (b) What is the total energy release? (c) Determine the energy output for each reaction and decay. (d) Why does tatg uvvp0 4ui ihd0po3axw+nr/2i34r x 0za- :he carbon cycle require a higher temperature ($T \approx 2 \times 10^7\ \text{K}$) than the proton-proton cycle ($T \approx 1.5 \times 10^7\ \text{K}$)?

(a) Compare the energy needed for the first reaction of the carbon cyw/y lt-o* ,fkjcle to that for a deuterium-tritium reactionk /-,t yfj*wlo.
(b) If a deuterium–tritium reaction requires $T \approx 3 \times 10^8\ \text{K}$, estimate the temperature needed for the first carbon-cycle reaction.

  A dose of 4.0 Sv of ,7tzy 5g6sbzl zuy,c+ovv),v$\gamma$ rays in a short period would be lethal to about half the people subjected to it. How many grays is this?    $Gy$

  Fifty rads of $\alpha$-particle radiation is equivalent to how many rads of X-rays in terms of biological damage?    rad

  How many rads of slow neutrons wi mqmiyqn r//63ll do as much biological damage as 75 rads of fast neutrons?mq6n3r/i /my q    rad slow neutrons

  How much energy is deposited in the body of a 65-kg adult exposed to a 2.0-Gy 4tomet bnte 75w3 ( 8,;rds.t)xs3spay6pk zndo t;s 5w bt8s6ex(d3 epsnt3oa47t)k,mrypz.n se?    $J$

  A $0.025-\mu\text{Ci}$ sample of $_{15}^{32}\text{P}$ is injected into an animal for tracer studies. If a Geiger counter intercepts 25% of the emitted $\beta^-$ particles, what will be the counting rate, assumed 85% efficient?$\approx$    $ \ \text{counts/s}$

  A cancer patient is undergoing radiation therapy in which proto xh2j1rxz2v )3fluq(pns with an energy of 1.2 MeV are incident on a 0.25-x2rxu 1 vp3jf)lzqh2(kg tumor.
(a) If the patient receives an effective dose of 1.0 rem, what is the absorbed dose?
(b) How many protons are absorbed by the tumor? Assume $QF = 1$.    $ \times 10^{10}\ \text{p}$

  A 1.0-mCi source of g8iuib;swhzj .r/r0tf h 2qqky( w*5d./q q-w$_{15}^{32}\text{P}$ (in $\text{NaHPO}_4$), a $\beta^-$ emitter, is implanted in a tumor where it is to administer 36 Gy. The half-life of $_{15}^{32}\text{P}$ is 14.3 days, and 1 mCi delivers about $10\ \text{mGy/min}$. Approximately how long should the source remain implanted?    day

About 35 eV is required to prodg (xgc: 3li(lduce one ion pair in air. Show that this is consistent with the two definitions l3 c(dl(xggi:of the roentgen given in the text.

  $_{27}^{57}\text{Co}$ emits 122-keV $\gamma$ rays. If a 70-kg person swallowed $1.85\ \mu\text{Ci}$ of $_{27}^{57}\text{Co}$, what would be the dose rate (Gy/day) averaged over the whole body? Assume that 50% of the $\gamma$ energy is deposited in the body.    $\times 10^{-2}\ \text{Gy/day}$

  What is the mass of k j d9gv22k.ema $1.00-\mu\text{Ci}\ _{6}^{14}\text{C}$ source?    $\times 10^{-10}\ \text{kg}$

  Huge amounts of radioactive xx 1l)1ppdz5d7-rt, rj ib5wc$_{53}^{131}\text{I}$ were released in the accident at Chernobyl in 1986. Chemically, iodine goes to the human thyroid. (Doctors can use it for diagnosis and treatment of thyroid problems.) In a normal thyroid, $_{53}^{131}\text{I}$ absorption can cause damage to the thyroid.
(a) Write down the reactions for the decay of $_{53}^{131}\text{I}$.
(b) Its half-life is 8.0 d; how long would it take for ingested $_{53}^{131}\text{I}$ to become 10% of the initial value? N $\approx$    $ \ \text{d}$
(c) Absorbing 1 mCi of $_{53}^{131}\text{I}$ can be harmful; what mass of iodine is this?   $ \times 10^{-12}\ \text{kg}$

  Assume a liter of milk typically has ahk.:j 8if7wg+ldkw(+ e2 twrgn activity of 2000 pCi due to $_{19}^{40}\text{K}$. If a person drinks two glasses (0.5 L) per day, estimate the total effective dose (in Sv and in rem) received in a year. As a crude model, assume the milk stays in the stomach 12 hr and is then released. Assume also that very roughly 10% of the 1.5 MeV released per decay is absorbed by the body. Compare your result to the normal allowed dose of 100 mrem per year. Make your estimate for
(a) a 50-kg adult, $\approx$    $ \times 10^{-7}\ \text{Sv/year}$ $\approx $    $ \times 10^{-5}\ \text{rem/year}$ $\approx $    $ \times 10^{-4}$ times the allowed dose
(b) a 5-kg baby.   $\times 10^{-4}\ \text{Sv}$    $\times 10^{-4}\ \text{rem}$    $ \times 10^{-4}\ \text{times the allowed dose}$

Radon gas, $_{86}^{222}\text{Rn}$, is considered a serious health hazard (see discussion in text). It decays by $\alpha$ emission.
(a) What is the daughter nucleus?
(b) Is the daughter nucleus stable or radioactive? If the latter, how does it decay, and what is its half-life?
(c) Is the daughter nucleus also a noble gas, or is it chemically reacting?
(d) Suppose 1.0 ng of $_{86}^{222}\text{Rn}$ seeps into a basement. What will be its activity? If the basement is then sealed, what will be the activity 1 month later?

  Calculate the wavelength of photons needed to produce NMRlpfwne2- 7vd ; transitions in free protons in a 1.000-T field. In what region of the spectrum does it l-ef;pdnv2 lw7ie? c =    $m$

  J. Chadwick discovered the neutron by bombardiscp- hrye+4 xv29a )uung $_{4}^{9}\text{Be}$ with the popular projectile of the day, alpha particles.
(a) If one of the reaction products was the then unknown neutron, what was the other product?
(b) What is the Q-value of this reaction?Q =    MeV

  Fusion temperatures are often given in keV. Determine the conversion a9l6wikmn 5p.wlteus, v;j ,1factor from kelvins to kv lw mp kn,;,w1eiats95.luj6eV using, as is common in this field, $KE = kT$ without the factor $\frac{3}{2}$. K =    $ \times 10^{-5}\ \text{keV/K}$

  One means of enriching+po 7oq,aspbs./ q 6wu uranium is by diffusion of the gas $\text{UF}_6$. Calculate the ratio of the speeds of molecules of this gas containing $_{92}^{235}\text{U}$ and $_{92}^{238}\text{U}$ on which this process depends.    :1

  (a) What mass of $_{92}^{235}\text{U}$ was actually fissioned in the first atomic bomb, whose energy was the equivalent of about 20 kilotons of TNT (1 kiloton of TNT releases $5 \times 10^{12}\ \text{J}$)? $\approx $    $\ \text{kg}$
(b) What was the actual mass transformed to energy?$\approx $    $\ \text{g}$

  In a certain town the average yearly background radiation consists of 2gfzk87 xp /uh2;g(oiu1 mrad of X-rays and(uhf/uk og 2pg8 ix7z; $\gamma$ rays plus 3.0 mrad of particles having a QF of 10. How many rem will a person receive per year on the average?dose(rem) =   $ \times 10^{-2}\ \text{rem/yr}$

  Deuterium makes up 0.0115% of natural hydrogen on average. Make:5h fwil/r s/uqs3 bh2 a rough estimate of the total deuterium in the Earth's oceans and estimate the total energy released if all of it were used in fusion rea :w sfih 5r2/b/sq3lhuctors.

The total mass of deuterium is about    $ \times 10^{16}\ \text{kg}$
The total energy is about    $\times 10^{30}\ \text{J}$

  A shielded $\gamma$-ray source yields a dose rate of $0.052\ \text{rad/h}$ at a distance of 1.0 m for an average-sized person. If workers are allowed a maximum dose of 5.0 rem in 1 year, how close to the source may they operate, assuming a 40-h work week? Assume that the intensity of radiation falls off as the square of the distance. (It actually falls off more rapidly than $\frac{1}{r^2}$ because of absorption in the air, so your answer will give a better-than-permissible value.)    m

Radon gas, $_{86}^{222}\text{Rn}$, is formed by $\alpha$ decay. (a) Write the decay equation. (b) Ignoring the kinetic energy of the daughter nucleus (it's so massive), estimate the kinetic energy of the $\alpha$ particle produced. (c) Estimate the momentum of the alpha and of the daughter nucleus. (d) Estimate the kinetic energy of the daughter, and show that your approximation in (b) was valid.

  Consider a system of nbmh xti qm)(i4uttgu7.g5u 2+uclear power plants that produce 3400 MW.
(a) What total mass of $_{92}^{235}\text{U}$ fuel would be required to operate these plants for 1 yr, assuming that 200 MeV is released per fission? $\approx$    $ \ \text{kg}$
(b) Typically 6% of the $_{92}^{235}\text{U}$ nuclei that fission produce $_{38}^{90}\text{Sr}$, a $\beta^-$ emitter with a half-life of 29 yr. What is the total radioactivity of the $_{38}^{90}\text{Sr}$ in curies, produced in 1 yr? (Neglect the fact that some of it decays during the 1-yr period.) $\dfrac{\Delta N}{\Delta t}$    $ \times 10^{6}\ \text{Ci}$

  In the net reaction,, for the proton-proton cycle in the Sun, the neu)24/yi3d2 fhrfq) 5 mvtgy gxltrinos escape from the Sun with energy of about 0.5 MeV. The remaining energy, 26.2 dr/ m3ltg25hi 2vq) fy4fg yx)MeV, is available within the Sun. Use this value to calculate the "heat of combustion" per kilogram of hydrogen fuel and compare it to the heat of combustion of coal, about $3 \times 10^7\ \text{J/kg}$.    $ \times 10^{-14}\ \text{J/g}$
This is about    $ \times 10^7$times the heat of combustion of coal.

  Energy reaches Earth from the Sun at apqw0q8 vrx)g6 9pzg ;o rate of about $1400\ \text{W/m}^2$. Calculate
(a) the total power output of the Sun,$\approx $    $ \times 10^{26}\ \text{W}$
(b) the number of protons consumed per second in the reaction of Eq.31- 7, assuming that this is the source of all the Sun's energy. $\approx $    $ \times 10^8\ \text{protons/s}$
(c) Assuming that the Sun's mass of $2 \times 10^{30}\ \text{kg}$ was originally all protons and that all could be involved in nuclear reactions in the Sun's core, how long would you expect the Sun to "glow" at its present rate? See previous Problem.$ \approx $    $ \times 10^{11}\ \text{yr}$

  Some stars, in a lata w xho2bcb qp,w0c,z+s*hp 27er stage of evolution, may begin to fuse two $_{6}^{12}\text{C}$ nuclei into one $_{12}^{24}\text{Mg}$ nucleus.
(a) How much energy would be released in such a reaction?
(b) What kinetic energy must two carbon nuclei each have when far apart, if they can then approach each other to within 6.0 fm, center-to-center? KE =    $ \times 10^{-13}$ =    MeV
(c) Approximately what temperature would this require?   $ \times 10^{10}\ \text{K}$

  An average adult body containsr7x67h8n k yeg about $0.10\ \mu\text{Ci}$ of $_{19}^{40}\text{K}$, which comes from food.
(a) How many decays occur per second?    $\ \text{decays/s}$
(b) The potassium decays produce beta particles with energies of around 1.4 MeV. Calculate the dose per year in sieverts for a 50-kg adult.    $\times 10^{-4}\ \text{Sv/y}$
Is this a significant fraction of the $3.6\ \text{mSv/year}$ background rate?    %

  When the nuclear reactor accident occurred at Chernobyl in lf.:-4 1qiy7uqah aju z2e6c l1986, $2.0 \times 10^7\ \text{Ci}$ were released into the atmosphere. Assuming that this radiation was distributed uniformly over the surface of the Earth, what was the activity per square meter? (The actual activity was not uniform; even within Europe wet areas received more radioactivity from rainfall). $\frac{\text{Activity}}{\text{m}^2}$=   $ \times 10^{3}\ \text{decays/s}$

  A star with a large helium abundancez ag8ihw0v3zfb pcu4q 5gh -;9 can burn helium in the reaction $3\ _{2}^{4}\text{He} \to _{6}^{12}\text{C} + \gamma$. What is the Q-value for this reaction? Q =    MeV

  A $1.0-\mu\text{Ci}\ _{55}^{137}\text{Cs}$ source is used for 2.0 hours by a 75-kg student in a physics lab. Radioactive $_{55}^{137}\text{Cs}$ decays by $\beta^-$ decay with a half-life of 30 years. The average energy of the emitted betas is about 190 keV per decay. The $\beta^-$ decay is quickly followed by a $\gamma$ ray with an energy of 660 keV. Assuming the student absorbs all emitted energy, what effective dose (in rem) is received during lab? dose $\approx $    $ \times 10^{-5}\ \text{rem}$

  A large amount of $_{38}^{90}\text{Sr}$ was released during the Chernobyl nuclear reactor accident in 1986. The $_{38}^{90}\text{Sr}$ enters the body through the food chain. How long will it take for 90% of the $_{38}^{90}\text{Sr}$ released during the accident to decay? See Appendix B.$\approx $    y

Three radioactive sources have the same activity, 25 mCi. Source a+8sj-+oh.(vlqtr ps A emits 1.0-MeVhss aj tp.8qorvl(+-+ $\gamma$ rays, source B emits 2.0-MeV $\gamma$ rays, and source C emits 2.0-MeV alphas. What is the relative danger of these sources?

  A 70-kg patient is to be g4 hy;vq mc*5t0mas sucsl5r y f-6v)j.iven a medical test involving the ingestion of $_{43}^{99\text{m}}\text{Tc}$ (Section 31-7) which decays by emitting a 140-keV gamma. The half-life for this decay is 6 hours. Assuming that about half the gamma photons exit the body without interacting with anything, what must be the initial activity of the Tc sample if the whole-body dose cannot exceed 50 mrem? Make the rough approximation that biological elimination of Tc can be ignored. Activity $\simeq $    $\ \text{mCi}$