Exam 31: Nuclear Energy; Effects and Uses of Radiation

A $70 - \mathrm { kg }$ researcher absorbs $4.5 \times 10 ^ { 8 }$ neutrons in a work day, each of energy $1.2 \mathrm { MeV }$ . The relative biological effectiveness (RBE) for these neutrons is 10. What is the equivalent dosage of the radiation exposure for this researcher, in millirem?

The energy radiated by a star, such as the sun, results chiefly from

Consider the nuclear reaction: $7 \mathrm { Li } + 1 \mathrm { p } \rightarrow 4 \mathrm { He } + 4 \mathrm { He }$ . The known atomic masses are 7 Li: $\quad 7.016005 \mathrm { u }$ ${ } _ { 2 } ^ { 4 } \mathrm { He } : \quad 4.002603 \mathrm { u }$ 1p: $\quad 1.007825 \mathrm { u }$ What is the $Q$ -value (or reaction energy) of this reaction? $\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / \mathrm { c } ^ { 2 } \right)$

A person receives an absorbed dose of protons of 20 millirads. The RBE of protons is 5. What is this person's equivalent dose in rem?

A hypothetical particle has a mass of $510 \mathrm { MeV } / \mathrm { c } ^ { 2 }$ . If such a particle at rest decays into two gamma-ray photons, what is the wavelength of each photon? $\left( 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J} , c = \right.$ $\left. 3.00 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , h = 6.626 \times 10 ^ { - 34 } \mathrm {~J} \cdot \mathrm { s } \right)$

If a $\Sigma ^ { - }$ particle at rest decays into a neutron and a $\pi ^ { - }$ , what is the total kinetic energy of the decay products? The masses of $\Sigma ^ { - }$ , neutron, and $\pi ^ { - }$ are $1197 \mathrm { MeV } / c ^ { 2 } , 940 \mathrm { MeV } / c ^ { 2 }$ , and $140 \mathrm { MeV } / c ^ { 2 }$ , respectively.

Consider the nuclear reaction ${ } _ { 1 } ^ { 3 } \mathrm { H } + { } _ { 1 } ^ { 3 } \mathrm { H } \rightarrow { } _ { 2 } ^ { 4 } \mathrm { He } + 2 { } _ { 0 } ^ { 1 } \mathrm { n }$ . The known atomic masses are ${ } _ { 2 } ^ { 4 } \mathrm { He } : \quad 4.002603 \mathrm { u }$ ${ } _ { 1 } ^ { 3 } \mathrm { H } : \quad 3.016049 \mathrm { u }$ ${ } _ { 0 } ^ { 1 } \mathrm { n } : \quad 1.008665 \mathrm { u }$ What is the energy released (positive) or absorbed (negative) in this nuclear reaction? $( 1 \mathrm { u } = 931.5$ $\mathrm { MeV } / \mathrm { c } ^ { 2 }$ )

If a 2.0-MeV neutron released in a fission reaction loses half its kinetic energy in each moderator collision, how many collisions are needed to reduce its kinetic energy to $1 / 25 \mathrm { eV }$ ?

Determine the missing product $X$ in the following nuclear reaction: ${ } _ { 7 } ^ { 13 } \mathrm {~N} +$ neutron $\rightarrow \mathrm { X } +$ alpha particle

Two deuterium nuclei, ${ } _ { 1 } ^ { 2 } \mathrm { H }$ , fuse to produce a tritium nucleus, ${ } _ { 1 } ^ { 3 } \mathrm { H }$ , plus an ordinary hydrogen nucleus, ${ } _ { 1 } ^ { 1 } \mathrm { H }$ . A neutral deuterium atom has a mass of $2.014102 \mathrm { u }$ ; a neutral tritium atom has a mass of $3.016050 \mathrm { u }$ ; a neutral hydrogen atom has a mass of $1.007825 \mathrm { u }$ ; a neutron has a mass of $1.008665 \mathrm { u }$ ; and a proton has a mass of $1.007277 \mathrm { u }$ . How much energy is released in this fusion process? (1 u = 931.5 MeV/ $/ c ^ { 2 }$ )

Determine the missing product X in the nuclear reaction ${ } _ { 92 } ^ { 238 } U + { } _ { 0 } ^ { 1 } n \rightarrow X + 2 \beta ^ { - }$

A proton strikes an oxygen-18 nucleus, producing fluorine-18 and another particle X. What is the other particle X?

In the nuclear reaction ${ } _ { 8 } ^ { 16 } \mathrm { O } + { } _ { 0 } ^ { 1 } \mathrm { n } \rightarrow \mathrm { X } + { } _ { 2 } ^ { 4 } \mathrm { He }$ , what is $\mathrm { X }$ ?

The maximum permissible workday dose for occupational exposure to radiation is $18 \mathrm { mrem }$ . A 54-kg laboratory technician absorbs $2.6 \mathrm {~mJ}$ of $0.30 - \mathrm { MeV }$ gamma rays in a work day. The relative biological effectiveness (RBE) for gamma rays is $1.00$ . What is the ratio of the equivalent dosage received by the technician to the maximum permissible equivalent dosage?

In the nuclear reaction ${ } _ { 19 } ^ { 38 } \mathrm {~K} + { } _ { 1 } ^ { 1 } \mathrm { H } \rightarrow \mathrm { X } + { } _ { 20 } ^ { 38 } \mathrm { Ca }$ , what is $\mathrm { X }$ ?

In the nuclear reaction ${ } _ { 8 } ^ { 16 } \mathrm { O } + { } _ { 2 } ^ { 4 } \mathrm { He } \rightarrow \mathrm { X } + { } _ { 10 } ^ { 19 } \mathrm { Ne }$ , what is $\mathrm { X }$ ?

Determine the missing product $X$ in the following nuclear reaction: ${ } _ { 5 } ^ { 10 } \mathrm {~B} +$ neutron $\rightarrow \mathrm { X } +$ alpha particle

In the fission reaction $235 \mathrm { U } + { } ^ { 1 } \mathrm { n } \rightarrow { } ^ { 141 } \mathrm { Ba } + 92 \mathrm { Kr } + x ^ { 1 } \mathrm { n }$ , what is the number $x$ of neutrons produced?

An excited ${ } _ { 92 } ^ { 236 } \mathrm { U } ^ { * }$ nucleus undergoes fission into two fragments as follows: ${ } _ { 92 } ^ { 236 } \mathrm { U } * \rightarrow { } _ { 56 } ^ { 144 } \mathrm { Ba } + { } _ { 36 } ^ { 92 } \mathrm { Kr }$ The following atomic masses are known: ${ } _ { 36 } ^ { 92 } \mathrm { Kr } : \quad 91.926270 \mathrm { u }$ ${ } _ { 56 } ^ { 144 } \mathrm { Ba } : \quad 143.922845 \mathrm { u }$ ${ } _ { 92 } ^ { 236 } \mathrm { U } ^ { * } : \quad 236.045563 \mathrm { u }$ What is the reaction energy released during this fission reaction? $\left( 1 \mathrm { u } = 931.5 \mathrm { MeV } / \mathrm { c } ^ { 2 } \right)$

The main fuel for producing energy in the center of the sun is