fizikzauglom

GRADE 9 PRACTICE

Physics Problems: Nuclear physics, Grade 9

Communication energy, reactions, energy and radiation protection.

18 problems across 4 sub-topics
Practise in the interactive mode

Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.

Problem statements

The answer options are there to check against, and the walkthrough opens under each problem.

18 problems
Position in this set: 1 from 18

Problem #58

Binding energy, fission and reactor

What concept does the description correspond to: “A heavy nucleus can split, releasing energy and neutrons that can cause new fissions.”?

Answer options

  1. \text{Fission and chain reaction}
  2. \text{Mass defect and binding energy}
  3. \text{Nuclear reactor}
  4. \text{Point particle}
Show the walkthroughHide the walkthrough
Given
\text{Description}
\text{A heavy nucleus can split, releasing energy and neutrons that can cause new fissions.}
Find

\text{name concepts}

  1. \text{Let's compare approval with definition}

    A self-sustaining chain requires critical conditions; critical mass depends not just on the amount of material, but also on shape, composition and neutron losses.

  2. \text{Let's formulate conclusion}\text{Concept} = \text{Fission and chain reaction}

Answer\text{Concept} = \text{Fission and chain reaction}

Position in this set: 2 from 18

Problem #59

Binding energy, fission and reactor

What concept does the description correspond to: “The mass of a bound nucleus is less than the sum of the masses of free nucleons, and the difference corresponds to the binding energy.”?

Answer options

  1. \text{Mass defect and binding energy}
  2. \text{Fission and chain reaction}
  3. \text{Nuclear reactor}
  4. \text{Point particle}
Show the walkthroughHide the walkthrough
Given
\text{Description}
\text{A bound nucleus has less mass than the sum of free nucleon masses; the difference corresponds to binding energy.}
Find

\text{name concepts}

  1. \text{Let's compare approval with definition}

    Binding energy per nucleon describes average binding strength. In an energy-releasing reaction, the total final particle mass is less than the initial mass; stability against radioactive decay cannot be determined from average binding energy alone.

  2. \text{Let's formulate conclusion}\text{Concept} = \text{Mass defect and binding energy}

Answer\text{Concept} = \text{Mass defect and binding energy}

Position in this set: 3 from 18

Problem #60

Nuclear physics

The mass defect of the system is 0.002 amu. Find the energy in MeV using 1 amu c² = 931.5 MeV.

Answer options

  1. 1{,}863\,\text{МэВ}
  2. 0{,}466\,\text{МэВ}
  3. 465{,}75\,\text{МэВ}
  4. 1863\,\text{МэВ}
Show the walkthroughHide the walkthrough
Given
\Delta m
0{,}002\,\text{а.е.м.}
1\,\text{а.е.м.}\cdot c^2
931{,}5\,\text{МэВ}
Find

E

  1. E=\Delta mc^2E=0{,}002\cdot931{,}5\,\text{МэВ}E = 1{,}863\,\text{МэВ}

Answer1{,}863\,\text{МэВ}

Position in this set: 4 from 18

Problem #61

Ionizing radiation and thermonuclear fusion

What concept does the description correspond to: “Ionizing radiation damages molecules and cells, and the risk depends on the dose, type and conditions of exposure.”?

Answer options

  1. \text{Biological effects of radiation}
  2. \text{Thermonuclear reaction}
  3. \text{Elementary particles and antiparticles}
  4. \text{Point particle}
Show the walkthroughHide the walkthrough
Given
\text{Description}
\text{Ionizing radiation damages molecules and cells; risk depends on dose, radiation type and exposure conditions.}
Find

\text{name concepts}

  1. \text{Let's compare approval with definition}

    Protection combines less time, greater distance and suitable shielding, while dose monitoring remains necessary.

  2. \text{Let's formulate conclusion}\text{Concept} = \text{Biological effects of radiation}

Answer\text{Concept} = \text{Biological effects of radiation}

Position in this set: 5 from 18

Problem #62

Ionizing radiation and thermonuclear fusion

What concept does the description correspond to: “Synthesis is the combination of light nuclei; energy is released if the total mass of the products is less than the mass of the original particles. High temperature helps overcome electrical repulsion."?

Answer options

  1. \text{Thermonuclear reaction}
  2. \text{Biological effects of radiation}
  3. \text{Elementary particles and antiparticles}
  4. \text{Point particle}
Show the walkthroughHide the walkthrough
Given
\text{Description}
\text{synthesis - association lungs cores; energy stands out, if total mass products less masses original particles. high temperature helps overcome electric repulsion.}
Find

\text{name concepts}

  1. \text{Let's compare approval with definition}

    Energy-releasing fusion reactions power stars. Not every combination of nuclei releases energy; controlled thermonuclear fusion depends on temperature, density and plasma confinement time.

  2. \text{Let's formulate conclusion}\text{Concept} = \text{Thermonuclear reaction}

Answer\text{Concept} = \text{Thermonuclear reaction}

Position in this set: 6 from 18

Problem #63

radioactivity

The mass of the radioactive isotope was 80 g. The half-life was 4 days. How much isotope will remain after 12 days?

Answer options

  1. 10\,\text{г}
  2. 20\,\text{г}
  3. 40\,\text{г}
  4. 60\,\text{г}
Show the walkthroughHide the walkthrough
Given
m_0
80\,\text{г}
T
4\,\text{сут}
t
12\,\text{сут}
Find

m

  1. n=\frac{t}{T}n=\frac{12}{4}n = 3
  2. m=m_0\cdot2^{-n}m=80\cdot2^{-3}\,\text{г}m = 10\,\text{г}

Answer10\,\text{г}

Position in this set: 7 from 18

Problem #178

Binding energy, fission and reactor

Specific binding energy 8 MeV/nucleon, mass number 16. Find the total binding energy.

Answer options

  1. 128\,\text{МэВ}
  2. 256\,\text{МэВ}
  3. 64\,\text{МэВ}
  4. 384\,\text{МэВ}
Show the walkthroughHide the walkthrough
Given
e
8\,\text{МэВ/нуклон}
A
16\,\text{нуклонов}
Find

E

  1. E=eAE=8 \cdot 16E=128\,\text{МэВ}

    We multiply the average energy by the number of nucleons.

Answer128\,\text{МэВ}

Position in this set: 8 from 18

Problem #179

Binding energy, fission and reactor

Specific binding energy 7{,}5 MeV/nucleon, mass number 20. Find the total binding energy.

Answer options

  1. 300\,\text{МэВ}
  2. 150\,\text{МэВ}
  3. 75\,\text{МэВ}
  4. 450\,\text{МэВ}
Show the walkthroughHide the walkthrough
Given
e
7{,}5\,\text{МэВ/нуклон}
A
20\,\text{нуклонов}
Find

E

  1. E=eAE=7{,}5 \cdot 20E=150\,\text{МэВ}

    We multiply the average energy by the number of nucleons.

Answer150\,\text{МэВ}

Position in this set: 9 from 18

Problem #180

Binding energy, fission and reactor

Sum of masses of free nucleons 4{,}032 amu, mass of the bound nucleus 4{,}002 a.e.m. Find the binding energy using 931{,}5 MeV per 1 amu mass defect.

Answer options

  1. 55{,}89\,\text{МэВ}
  2. 27{,}945\,\text{МэВ}
  3. 13{,}9725\,\text{МэВ}
  4. 83{,}835\,\text{МэВ}
Show the walkthroughHide the walkthrough
Given
m_1
4{,}032\,\text{а.е.м.}
m_2
4{,}002\,\text{а.е.м.}
k
931{,}5\,\text{МэВ/а.е.м.}
Find

E

  1. \Delta m=m_1-m_2\Delta m=4{,}032 - 4{,}002\Delta m=0{,}03\,\text{а.е.м.}

    The bound nucleus has less mass.

  2. E=\Delta m\cdot kE=0{,}03 \cdot 931{,}5E=27{,}945\,\text{МэВ}

    We use the equivalence of mass and energy.

Answer27{,}945\,\text{МэВ}

Position in this set: 10 from 18

Problem #181

Binding energy, fission and reactor

Sum of masses of free nucleons 12{,}1 amu, mass of the bound nucleus 12 a.e.m. Find the binding energy using 931{,}5 MeV per 1 amu mass defect.

Answer options

  1. 186{,}3\,\text{МэВ}
  2. 46{,}575\,\text{МэВ}
  3. 93{,}15\,\text{МэВ}
  4. 279{,}45\,\text{МэВ}
Show the walkthroughHide the walkthrough
Given
m_1
12{,}1\,\text{а.е.м.}
m_2
12\,\text{а.е.м.}
k
931{,}5\,\text{МэВ/а.е.м.}
Find

E

  1. \Delta m=m_1-m_2\Delta m=12{,}1 - 12\Delta m=0{,}1\,\text{а.е.м.}

    The bound nucleus has less mass.

  2. E=\Delta m\cdot kE=0{,}1 \cdot 931{,}5E=93{,}15\,\text{МэВ}

    We use the equivalence of mass and energy.

Answer93{,}15\,\text{МэВ}

Position in this set: 11 from 18

Problem #182

Binding energy, fission and reactor

In one division stands out 200 MeV. Happened 1000000000000 divisions. Electrical efficiency 30 %. Find the electrical energy in joules. 1 MeV = 1{,}602\cdot 10^{-13} J.

Answer options

  1. 19{,}224\,\text{Дж}
  2. 4{,}806\,\text{Дж}
  3. 9{,}612\,\text{Дж}
  4. 28{,}836\,\text{Дж}
Show the walkthroughHide the walkthrough
Given
E
200\,\text{МэВ}
N
1000000000000\,\text{делений}
e
30\,\text{\%}
k
1{,}602\cdot 10^{-13}\,\text{Дж/МэВ}
Find

W

  1. Q_1=EkQ_1=200 \cdot 1{,}602\cdot 10^{-13}Q_1=3{,}204\cdot 10^{-11}\,\text{Дж}

    Convert the energy of one division to joules.

  2. Q=Q_1NQ=3{,}204\cdot 10^{-11} \cdot 1000000000000Q=32{,}04\,\text{Дж}

    We find all the released energy.

  3. W=Q\frac{\eta}{100}W=\frac{32{,}04 \cdot 30}{100}W=9{,}612\,\text{Дж}

    Part of the thermal energy is converted into electrical energy.

Answer9{,}612\,\text{Дж}

Position in this set: 12 from 18

Problem #183

Binding energy, fission and reactor

In one division stands out 200 MeV. Happened 2000000000000 divisions. Electrical efficiency 40 %. Find the electrical energy in joules. 1 MeV = 1{,}602\cdot 10^{-13} J.

Answer options

  1. 51{,}264\,\text{Дж}
  2. 12{,}816\,\text{Дж}
  3. 76{,}896\,\text{Дж}
  4. 25{,}632\,\text{Дж}
Show the walkthroughHide the walkthrough
Given
E
200\,\text{МэВ}
N
2000000000000\,\text{делений}
e
40\,\text{\%}
k
1{,}602\cdot 10^{-13}\,\text{Дж/МэВ}
Find

W

  1. Q_1=EkQ_1=200 \cdot 1{,}602\cdot 10^{-13}Q_1=3{,}204\cdot 10^{-11}\,\text{Дж}

    Convert the energy of one division to joules.

  2. Q=Q_1NQ=3{,}204\cdot 10^{-11} \cdot 2000000000000Q=64{,}08\,\text{Дж}

    We find all the released energy.

  3. W=Q\frac{\eta}{100}W=\frac{64{,}08 \cdot 40}{100}W=25{,}632\,\text{Дж}

    Part of the thermal energy is converted into electrical energy.

Answer25{,}632\,\text{Дж}

Position in this set: 13 from 18

Problem #184

Ionizing radiation and thermonuclear fusion

Sample mass 2 kg absorbed 0{,}004 J of radiation energy. Find the absorbed dose D = E/m in gray.

Answer options

  1. 0{,}004\,\text{Гр}
  2. 0{,}002\,\text{Гр}
  3. 0{,}001\,\text{Гр}
  4. 0{,}006\,\text{Гр}
Show the walkthroughHide the walkthrough
Given
m
2\,\text{кг}
E
0{,}004\,\text{Дж}
Find

D

  1. D=\frac{E}{m}D=\frac{0{,}004}{2}D=0{,}002\,\text{Гр}

    One gray is equal to one joule per kilogram.

Answer0{,}002\,\text{Гр}

Position in this set: 14 from 18

Problem #185

Ionizing radiation and thermonuclear fusion

Sample mass 4 kg absorbed 0{,}012 J of radiation energy. Find the absorbed dose D = E/m in gray.

Answer options

  1. 0{,}006\,\text{Гр}
  2. 0{,}0015\,\text{Гр}
  3. 0{,}003\,\text{Гр}
  4. 0{,}009\,\text{Гр}
Show the walkthroughHide the walkthrough
Given
m
4\,\text{кг}
E
0{,}012\,\text{Дж}
Find

D

  1. D=\frac{E}{m}D=\frac{0{,}012}{4}D=0{,}003\,\text{Гр}

    One gray is equal to one joule per kilogram.

Answer0{,}003\,\text{Гр}

Position in this set: 15 from 18

Problem #186

Ionizing radiation and thermonuclear fusion

After each identical protective layer, half the initial number of particles for this layer is recorded. Before the defense was registered 800 particles per second. How long will it be after two coats?

Answer options

  1. 400\,\text{частиц/с}
  2. 100\,\text{частиц/с}
  3. 200\,\text{частиц/с}
  4. 600\,\text{частиц/с}
Show the walkthroughHide the walkthrough
Given
N
800\,\text{частиц/с}
Find

N_2

  1. N_1=\frac{N}{2}N_1=\frac{800}{2}N_1=400\,\text{частиц/с}

    The first layer reduces the intensity by half.

  2. N_2=\frac{N_1}{2}N_2=\frac{400}{2}N_2=200\,\text{частиц/с}

    The second acts on a weakened flow.

Answer200\,\text{частиц/с}

Position in this set: 16 from 18

Problem #187

Ionizing radiation and thermonuclear fusion

After each identical protective layer, half the initial number of particles for this layer is recorded. Before the defense was registered 1200 particles per second. How long will it be after two coats?

Answer options

  1. 600\,\text{частиц/с}
  2. 150\,\text{частиц/с}
  3. 900\,\text{частиц/с}
  4. 300\,\text{частиц/с}
Show the walkthroughHide the walkthrough
Given
N
1200\,\text{частиц/с}
Find

N_2

  1. N_1=\frac{N}{2}N_1=\frac{1200}{2}N_1=600\,\text{частиц/с}

    The first layer reduces the intensity by half.

  2. N_2=\frac{N_1}{2}N_2=\frac{600}{2}N_2=300\,\text{частиц/с}

    The second acts on a weakened flow.

Answer300\,\text{частиц/с}

Position in this set: 17 from 18

Problem #188

Ionizing radiation and thermonuclear fusion

In one synthesis reaction, 17{,}6 MeV. Happened 1000000000000 reactions, 0{,}5 fraction of energy transferred to the heated substance. Find the transferred energy in joules. 1 MeV = 1{,}602\cdot 10^{-13} J.

Answer options

  1. 2{,}81952\,\text{Дж}
  2. 0{,}70488\,\text{Дж}
  3. 4{,}22928\,\text{Дж}
  4. 1{,}40976\,\text{Дж}
Show the walkthroughHide the walkthrough
Given
E
17{,}6\,\text{МэВ}
N
1000000000000\,\text{реакций}
r
0{,}5\,\text{доля}
k
1{,}602\cdot 10^{-13}\,\text{Дж/МэВ}
Find

W

  1. e=Eke=17{,}6 \cdot 1{,}602\cdot 10^{-13}e=2{,}81952\cdot 10^{-12}\,\text{Дж}

    Convert the reaction energy into SI.

  2. Q=eNQ=2{,}81952\cdot 10^{-12} \cdot 1000000000000Q=2{,}81952\,\text{Дж}

    We add up the energies of all reactions.

  3. W=QrW=2{,}81952 \cdot 0{,}5W=1{,}40976\,\text{Дж}

    We take into account the share of transferred energy.

Answer1{,}40976\,\text{Дж}

Position in this set: 18 from 18

Problem #189

Ionizing radiation and thermonuclear fusion

In one synthesis reaction, 17{,}6 MeV. Happened 2000000000000 reactions, 0{,}75 fraction of energy transferred to the heated substance. Find the transferred energy in joules. 1 MeV = 1{,}602\cdot 10^{-13} J.

Answer options

  1. 4{,}22928\,\text{Дж}
  2. 8{,}45856\,\text{Дж}
  3. 2{,}11464\,\text{Дж}
  4. 12{,}6878\,\text{Дж}
Show the walkthroughHide the walkthrough
Given
E
17{,}6\,\text{МэВ}
N
2000000000000\,\text{реакций}
r
0{,}75\,\text{доля}
k
1{,}602\cdot 10^{-13}\,\text{Дж/МэВ}
Find

W

  1. e=Eke=17{,}6 \cdot 1{,}602\cdot 10^{-13}e=2{,}81952\cdot 10^{-12}\,\text{Дж}

    Convert the reaction energy into SI.

  2. Q=eNQ=2{,}81952\cdot 10^{-12} \cdot 2000000000000Q=5{,}63904\,\text{Дж}

    We add up the energies of all reactions.

  3. W=QrW=5{,}63904 \cdot 0{,}75W=4{,}22928\,\text{Дж}

    We take into account the share of transferred energy.

Answer4{,}22928\,\text{Дж}

The theory behind these problems

Work through the topic if a problem will not give in.

Binding energy, fission and reactorMass defect, chain reactions, critical conditions and nuclear power.Ionizing radiation and thermonuclear fusionBiological effects, protection, fusion, particles and antiparticles.

Formulas by topic

Look up symbols and units of measurement in the reference.

EnergyE, W · Дж