Nuclear physics

A sodium nucleus is represented as ²³₁₁Na.
How many neutrons are in this nucleus?

Which statement about two isotopes of the same element is correct?

A neutral atom loses one electron.
What is formed?

Which statement describes nuclear fusion?

What is meant by the nucleon number of a nucleus?

A lithium atom is represented as ⁷₃Li.

Which type of radiation produces the most ionisation as it passes through air?

A radioactive source emits only one type of radiation. The radiation passes through a sheet of paper. It is stopped by a sheet of aluminium 5 mm thick.
Which type of radiation does the source emit?

The corrected count rate from a radioactive sample is 640 counts/min. The half-life of the isotope is 3.0 hours.
What is the corrected count rate after 9.0 hours?

A laboratory technician uses a source that emits γ-rays.
Which action reduces her exposure to the radiation most effectively?

This question is about the three types of nuclear radiation.

A student uses a Geiger–Müller tube connected to a counter to investigate background radiation in a laboratory.

A water-treatment engineer notes that a chlorine atom is written ³⁵₁₇Cl. How many neutrons are in the nucleus of this atom?

A student has three radioactive sources. Which type of radiation is completely stopped by a single sheet of paper?

A hospital technician regularly handles a sealed gamma-emitting source. Which action does most to reduce the radiation she receives?

Which statement describes nuclear fusion in the core of the Sun?

A piece of aircraft metal contains aluminium-27 atoms, written ²⁷₁₃Al.

A student investigates background radiation using a Geiger–Müller counter.

In the core of a star, hydrogen nuclei undergo nuclear fusion.

Iodine-131 is used in pharmacology to treat an overactive thyroid. An atom of iodine-131 has nucleon number 131 and proton number 53.
How many neutrons are in one nucleus of iodine-131?

Four nuclides are described.
W: 6 protons, 6 neutrons
X: 6 protons, 8 neutrons
Y: 7 protons, 7 neutrons
Z: 8 protons, 8 neutrons
Which two nuclides are isotopes of the same element?

A water company wants to find a leak in a buried pipe by adding a radioactive tracer to the water and scanning the ground above with a detector. Which type of radiation should the tracer emit?

Iodine-131 is a radioactive isotope used to treat an overactive thyroid gland. A nucleus of iodine-131 has nucleon number 131 and proton number 53.

Fluoride compounds are added to some water supplies. A neutral atom of fluorine-19 has nucleon number 19 and proton number 9.

Cobalt-60 is used as a gamma source in cancer treatment. A nucleus of cobalt-60 is written ⁶⁰₂₇Co.
How many neutrons are in one nucleus of cobalt-60?

A radioactive tracer used in a hospital has a half-life of 6.0 hours. What percentage of the original radioactive nuclei remains after 18 hours?

Iodine-131, ¹³¹₅₃I, is a radioactive isotope given to patients to treat an overactive thyroid gland.

A water company adds a radioactive tracer to water in a pipe to study how the water flows. The tracer has a half-life of 5.0 hours. A sample of the water initially has an activity of 960 counts per second.

A hospital pharmacy prepares capsules that contain a gamma-emitting radioactive substance.

A hospital uses a technetium isotope whose nucleus contains 43 protons and has a nucleon number of 99. How many neutrons are in one nucleus of this isotope?

In a hospital physics laboratory a radioactive source is placed in front of a detector. A sheet of paper placed in between hardly changes the count rate, but a 3 mm thick aluminium plate reduces it to the background level. Which radiation does the source emit?

A hospital technician must handle a radioactive source. Which action gives the technician the smallest radiation dose?

An iodine-131 nucleus is used in a hospital treatment. It contains 53 protons and has a nucleon number of 131.

A radiographer works with sealed radioactive sources in a hospital.

A neutral atom of aluminium, used in aircraft skin, has a proton number of 13 and a nucleon number of 27. How many electrons does the atom have?

A narrow beam of radiation from a source used to follow fertiliser in soil passes between two charged metal plates. The beam is not deflected. Which statement is correct?

An aircraft exit sign contains a radioactive source. Which statement defines the half-life of the source?

Old aircraft instrument dials were painted with radium-226 paint. A radium-226 nucleus has 88 protons and a nucleon number of 226.

A grain store uses a sealed radioactive source to monitor the level of grain in a silo.

Which pair of nuclides are isotopes of the same element?

Which statement correctly describes the half-life of a radioactive isotope?

Iodine-131, ¹³¹₅₃I, is used in medicine. A stable isotope of iodine is iodine-127.

A shopping centre has a Geiger-Müller counter that records the background radiation. It records 126 counts in 6.0 minutes.

Archaeologists date wooden objects using carbon-14, ¹⁴₆C. How many neutrons are in one nucleus of carbon-14?

The smoke detectors in a data centre contain a source of alpha particles. Which statement about alpha particles is correct?

A carbon nucleus has 6 protons and 8 neutrons. A second carbon nucleus has 6 protons and 6 neutrons.

Some old bicycle lamps use a glass tube containing tritium, a radioactive isotope of hydrogen, to glow in the dark. The half-life of tritium is 12 years. A new tube has an activity of 800 Bq.

A marine biologist tags crabs with strontium-90. Each atom has 38 protons and 52 neutrons in its nucleus. What is the nucleon number of this isotope?

Driftwood samples are dated using carbon-12 and carbon-14. Which statement correctly describes these two isotopes?

Wooden beams in an old harbour warehouse are dated using carbon-14. A neutral atom of carbon-14 has nucleon number 14 and proton number 6.

Aluminium foil used to package frozen cargo is checked on a production line using a radioactive source.

A marine biologist injects fish with a radioactive tracer that has a half-life of 8.0 days. The initial activity of the tracer in one fish is 640 Bq.

An archaeologist analyses a bronze artefact that contains copper-63, written ⁶³₂₉Cu. Which row gives the particles in one neutral atom of this nuclide?

Wood from an archaeological site contains atoms of carbon-12 and carbon-14. Which statement about these two nuclides is correct?

A technician in a hospital handles a sealed radioactive source. Which action would NOT reduce the technician's exposure to radiation?

A data centre fire alarm contains americium-241, written ²⁴¹₉₅Am. Americium-243 is another nuclide of the same element.

A conservator tests three unknown sources, P, Q and R, using a counter. The results are:
Source P: the count rate falls to the background level when a sheet of paper is placed in front of it.
Source Q: paper has no effect, but 3 mm of aluminium reduces the count rate to the background level.
Source R: aluminium of thickness 3 mm has almost no effect, but a thick block of lead reduces the count rate a lot.

A sample of sea-floor sediment contains the nuclide strontium-90, written ⁹⁰₃₈Sr. How many neutrons are in one nucleus of this nuclide?

A marine-biology laboratory compares four nuclides. The numbers of protons and nucleons (protons plus neutrons) are:
P: 6 protons, 12 nucleons
Q: 7 protons, 14 nucleons
R: 6 protons, 14 nucleons
S: 8 protons, 16 nucleons
Which two nuclides are isotopes of the same element?

Carbon-14, written ¹⁴₆C, is found in shells on the sea floor.

In an experiment, alpha particles are fired at a very thin sheet of gold foil in a vacuum, and a detector records where they emerge. Gold has the nuclide ¹⁹⁷₇₉Au.

A cobalt nuclide used to sterilise food has proton number 27 and nucleon number 60. How many neutrons are in one nucleus of this nuclide?

Four nuclides are described by their numbers of protons and neutrons.
P: 19 protons, 20 neutrons
Q: 20 protons, 19 neutrons
R: 19 protons, 22 neutrons
S: 18 protons, 22 neutrons
Which two nuclides are isotopes of the same element?

Sodium-24 is a radioactive isotope that food technologists add in tiny amounts to a liquid to trace its flow through a processing pipe. A nucleus of sodium-24 has proton number 11 and nucleon number 24. Stable sodium-23 has the same proton number.

A student studies a sample of iodine-131. The table shows the count rate from the sample after the background count rate has been subtracted.
Time / days: 0, 8, 16, 24
Corrected count rate / counts per minute: 960, 480, 240, 120

A school science department stores small radioactive sources that emit alpha, beta or gamma radiation.

A sample of gas from a volcanic vent contains radon. One nuclide of radon is written ²²²₈₆Rn. How many neutrons are in the nucleus of this nuclide?

Two atoms of sulfur are ³²₁₆S and ³⁴₁₆S. Which statement about these atoms is correct?

A dock worker has to move a sealed container holding a gamma-emitting source. Which action best reduces the radiation dose she receives?

A theatre's smoke detector contains a small sample of americium-241, written ²⁴¹₉₅Am. Americium-243 is another form of americium.

A geologist samples a radioactive gas from a volcanic vent. After correcting for background, the count rate from the gas was 640, 320, 160 and 80 counts/min at times of 0, 4, 8 and 12 days after collection.

A neutral atom of chlorine-35 has 17 protons and 18 neutrons. Which nucleus is an isotope of this atom?

A nucleus decays by emitting a beta-minus particle. How do the proton number and the nucleon number of the nucleus change?

A technician handles a gamma-emitting source in a hospital laboratory. Which procedure is the best way to reduce the radiation dose received?

Which statement describes nuclear fusion, the process that releases energy in the Sun?

Iodine-131 is a radioactive isotope used in the treatment of thyroid conditions. A nucleus of iodine-131 is written ¹³¹₅₃I. Iodine-127 is a stable isotope of iodine.

Phosphorus-32, ³²₁₅P, is used as a tracer to follow how crops take up fertiliser. How many protons, neutrons and electrons are in a neutral atom of this nuclide?

A soil scientist studies carbon-12 and carbon-14 in a field sample. Which statement about these two isotopes of carbon is correct?

A radioactive source emits radiation that passes through a sheet of paper but is almost completely stopped by a 3 mm sheet of aluminium. What is the radiation?

Aircraft cabins contain smoke detectors. Each detector has a small source of americium-241, ²⁴¹₉₅Am, which emits alpha particles.

A shop sells ornaments made of copper. One atom of copper-63 is written ⁶³₂₉Cu. How many neutrons are in the nucleus of this atom?

In a scattering experiment, alpha particles are fired at a very thin gold foil. Almost all of them pass straight through, but a tiny fraction are deflected through large angles. Which conclusion is supported by these results?

A technician in a hospital must handle a gamma-emitting source. Which set of actions gives the lowest exposure to radiation?

A shop sells lithium batteries. A neutral atom of lithium-7 is written ⁷₃Li.

A factory makes thin aluminium foil. A radioactive source on one side of the foil and a detector on the other side are used to monitor the thickness of the foil as it is made.

A neutral atom of sodium is written ²³₁₁Na. How many protons, neutrons and electrons does it contain?

A school technician has to move a sealed radioactive source for a demonstration. Which action is the safest?

An atom of aluminium, ²⁷₁₃Al, loses three electrons and becomes an ion. How many protons and electrons does the ion contain?

A theatre’s prop store holds an old stage clock whose dial is painted with a radioactive paint. The paint emits alpha, beta and gamma radiation.

A marine laboratory keeps a sealed sample of strontium-90. Each nucleus contains 38 protons and has a nucleon number of 90. How many neutrons are in one nucleus?

Timber from a shipwreck is dated by comparing the carbon-14 and carbon-12 in it. Which statement correctly compares atoms of carbon-12 and carbon-14?

A coastal power station generates electricity from uranium-235. Which statement describes nuclear fission in the reactor?

A smoke detector in an office building contains a small sample of americium-241. An atom of this isotope has a proton number of 95 and a nucleon number of 241.

An energy company is comparing nuclear fission and nuclear fusion for supplying power to a new city district.

Potassium-40 is used to date volcanic rock. A neutral atom of ⁴⁰₁₉K contains which numbers of particles?

A shipyard checks welds in a steel hull 25 mm thick by placing a radioactive source on one side and a detector on the other. Which radiation is suitable for this test?

A technician must handle a sealed radioactive source. Which set of precautions is correct?

Argon-40 is formed in volcanic rock when potassium-40 decays, which allows the rock to be dated. The proton number of argon is 18.

A theatre's smoke detector contains a small americium-241 source that emits alpha particles into an air gap between two electrodes. A small steady current flows across the gap.

A hospital uses iodine-123 and iodine-131 in different tests. The two are isotopes of iodine. Which statement about the nuclei of these isotopes is correct?

A factory that makes foil for shops monitors the foil thickness using a radioactive source. The radiation from the source passes through a sheet of paper, is stopped by 5 mm of aluminium and is deflected by a magnetic field. Which type of radiation is it?

A wooden beam used in a biomass power plant contains atoms of carbon-12 and carbon-14. A neutral atom of carbon-14 has nucleon number 14 and proton number 6.

A shop sells granite worktops. A student suspects the granite emits more radiation than the surroundings and tests it with a radiation detector.

A neutral atom of plutonium-238 (nucleon number 238, proton number 94) is the heat source in the power unit of a space probe. How many neutrons are in the nucleus of one atom?

Which pair of atoms are isotopes of the same element?

Plutonium-238 (nucleon number 238, proton number 94) is used as the heat source in the power unit of a deep-space probe.

A bridge engineer is told about the three types of radiation from radioactive sources.

A team inspects a bridge using a sealed gamma source.

Chlorine has two common isotopes, ³⁵₁₇Cl and ³⁷₁₇Cl.

A detector placed near a radioactive source gives a reading of 340 counts/min. The background count rate is 20 counts/min. The half-life of the source is 2 days.
What reading does the detector give 4 days later?

A factory produces paper sheet. A radioactive source on one side of the sheet and a detector on the other side are used to monitor its thickness continuously for many years.
Which source is most suitable?

A hospital uses a radioactive tracer to examine a patient's kidneys. The tracer emits only γ-rays and has a half-life of 6.0 hours. It is injected into the patient. A detector outside the body records the radiation.

A radioactive tracer injected into a patient has an activity of 80 kBq and a half-life of 6.0 hours. Assuming the activity falls only because of radioactive decay, what is the activity after 24 hours?

A sample contains 2000 undecayed nuclei of an isotope with a half-life of 10 s. Which statement about the decay is correct?

A nuclear power station uses uranium-235 as its fuel.

In a scattering experiment a narrow beam of alpha particles is fired at a very thin sheet of gold foil. Most alpha particles pass straight through, a small number are deflected through large angles and a very few rebound almost straight back.

A radiopharmaceutical has an activity of 240 MBq when prepared. Its half-life is 6.0 hours. What is its activity 18 hours later?

Which statement correctly describes nuclear fission in a power station reactor?

Hydrogen nuclei in the Sun fuse only at extremely high temperatures. What is the main reason for this?

A water company adds a small amount of a gamma-emitting tracer to the water in a buried pipe. A detector held above the ground finds the leak where the count rate is highest. A sample of the tracer gives a count rate of 134 counts/min. The background count rate is 22 counts/min. After 12 hours the same sample gives 36 counts/min.

A game designer models radioactive decay. The game starts with 320 glowing tokens. In each turn, on average, half of the tokens still in play are removed.

A water company wants to find a leak in a buried plastic pipe. A radioactive tracer is added to the water and a detector is carried along the ground above the pipe. Which tracer is most suitable?

With no source present, a detector records 24 counts in 2.0 minutes. When a source is placed near it, the detector records 150 counts in 1.0 minute. What is the count rate due to the source alone?

In a survival video game, a player's radiation meter rises to 720 units in a contaminated zone. After the player leaves the zone, the reading halves every 8.0 minutes. The designers modelled this on radioactive decay.

A technician measures the activity of a sample of a radioactive tracer used in medical scans.
Time / h: 0, 2.0, 4.0, 6.0, 8.0
Activity / kBq: 80, 57, 40, 28, 20

The carbon-fibre panels on a racing car contain atoms of carbon-12 and carbon-14. Which statement correctly describes these two types of atom?

A hospital sample of a radioactive isotope has an activity of 640 MBq. Its half-life is 6.0 hours. What is its activity 24 hours later?

A honey factory checks the fill level of metal cans on a conveyor belt. A radioactive source is on one side of each can and a detector on the other side.

Solar panels power the sensors in a beekeeper's hive. The Sun releases energy by nuclear fusion.

A violin maker dates a wooden violin using carbon-14. Carbon-12 and carbon-14 are isotopes of carbon. Which statement is correct about their nuclei?

A radioactive sensor in an aircraft contains an isotope with a half-life of 2 hours. Which statement about one particular nucleus is correct?

A student follows a radioactive tracer taken up by a crop plant. The corrected count rate from a leaf is measured at intervals.