Nuclear Physics Practice Questions
20 free Nuclear Physics practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which particle determines the atomic number of an element?
- A Neutron
- B Electron
- C Proton
- D Quark
Correct answer: Proton
The atomic number of an element is defined by the number of protons present in its nucleus. Protons carry a positive charge and uniquely identify each chemical element.
Which type of radioactive decay emits a helium nucleus?
- A Beta decay
- B Gamma decay
- C Electron capture
- D Alpha decay
Correct answer: Alpha decay
Alpha decay involves the emission of an alpha particle, which consists of two protons and two neutrons. This particle is essentially the nucleus of a helium atom.
What is the unit commonly used to measure radioactivity?
- A Tesla
- B Becquerel
- C Electronvolt
- D Volt
Correct answer: Becquerel
The becquerel (Bq) is the SI unit of radioactivity and represents one nuclear disintegration per second. It measures how many atoms in a radioactive material decay over time.
In beta minus decay, what particle is emitted from the nucleus?
- A Proton
- B Neutron
- C Alpha particle
- D Electron
Correct answer: Electron
In beta minus decay, a neutron in the nucleus converts into a proton and emits an electron and an antineutrino. The emitted electron is called a beta particle.
Which radiation has the greatest penetrating power?
- A Alpha radiation
- B Beta radiation
- C Gamma radiation
- D Ultraviolet radiation
Correct answer: Gamma radiation
Gamma radiation consists of very high-energy electromagnetic waves. Because it has no mass and no charge, it passes far deeper into matter than alpha particles, beta particles or ultraviolet light, which are stopped by thin layers of material.
What does the half-life of a radioactive substance represent?
- A Time for the sample to decay completely
- B Time for the count rate to double
- C Time for half the atoms to decay
- D Time for radiation to stop
Correct answer: Time for half the atoms to decay
Half-life is the time required for half of the radioactive nuclei in a sample to decay. It is a characteristic property of each radioactive isotope.
Which particle has no electric charge?
- A Proton
- B Electron
- C Neutron
- D Alpha particle
Correct answer: Neutron
Neutrons are neutral subatomic particles found in the atomic nucleus. Unlike protons and electrons, they carry no electric charge.
Which nuclear process powers the Sun?
- A Nuclear fission
- B Beta decay
- C Electron capture
- D Nuclear fusion
Correct answer: Nuclear fusion
The Sun produces energy through nuclear fusion, where hydrogen nuclei combine to form helium. This process releases a large amount of energy according to Einstein's mass–energy equivalence principle.
Which nuclear reaction involves the splitting of a heavy nucleus into smaller nuclei?
- A Fusion
- B Ionization
- C Decay
- D Fission
Correct answer: Fission
Nuclear fission occurs when a heavy nucleus, such as uranium-235, splits into two smaller nuclei. This process releases energy along with additional neutrons.
Which isotope is commonly used as fuel in nuclear reactors?
- A Carbon-14
- B Strontium-90
- C Oxygen-16
- D Uranium-235
Correct answer: Uranium-235
Uranium-235 is a fissile isotope capable of sustaining a nuclear chain reaction. It is widely used as fuel in nuclear power plants.
Gamma rays are best described as:
- A High-energy electrons from the nucleus
- B High-energy electromagnetic waves
- C Positively charged helium nuclei
- D Fast-moving neutral atoms
Correct answer: High-energy electromagnetic waves
Gamma rays are high-energy electromagnetic radiation emitted during nuclear transitions. They have very short wavelengths and high penetrating power.
Which device is commonly used to detect nuclear radiation?
- A Thermometer
- B Geiger counter
- C Aneroid barometer
- D Voltmeter
Correct answer: Geiger counter
A Geiger counter detects ionizing radiation such as alpha, beta, and gamma rays. It works by measuring the ionization produced in a gas-filled tube.
What happens to the atomic number during beta minus decay?
- A It decreases by 1
- B It increases by 1
- C It remains unchanged
- D It decreases by 2
Correct answer: It increases by 1
During beta minus decay, a neutron converts into a proton and an electron. Because a proton is created, the atomic number increases by one.
Which type of radiation can be stopped by a sheet of paper?
- A Gamma radiation
- B Beta radiation
- C Alpha radiation
- D Neutron radiation
Correct answer: Alpha radiation
Alpha particles are relatively heavy and carry a +2 charge, causing them to lose energy quickly when interacting with matter. As a result, even a sheet of paper can stop them.
Which fundamental force holds protons and neutrons together in the nucleus?
- A Gravitational force
- B Electromagnetic force
- C Strong nuclear force
- D Weak nuclear force
Correct answer: Strong nuclear force
The strong nuclear force binds protons and neutrons together within the atomic nucleus. It is extremely powerful but acts only over very short distances.
Which of the following particles is emitted during beta plus decay?
- A Electron
- B Neutron
- C Positron
- D Alpha particle
Correct answer: Positron
In beta plus decay, a proton in the nucleus converts into a neutron and emits a positron and a neutrino. The positron is the antimatter counterpart of the electron.
Which nuclear reaction releases energy by combining light nuclei?
- A Nuclear fusion
- B Nuclear fission
- C Radioactive decay
- D Ionization
Correct answer: Nuclear fusion
Nuclear fusion occurs when light nuclei, such as hydrogen isotopes, combine to form heavier nuclei. The process releases a large amount of energy due to mass conversion into energy.
Which property of a nucleus affects its stability most directly?
- A Number of orbital electrons
- B Neutron-to-proton ratio
- C Ambient temperature
- D Type of chemical bonding
Correct answer: Neutron-to-proton ratio
The ratio of neutrons to protons plays a crucial role in nuclear stability. Too many or too few neutrons relative to protons can make a nucleus unstable and lead to radioactive decay.
Which particle is typically released during nuclear fission to sustain a chain reaction?
- A Electrons
- B Neutrons
- C Protons
- D Photons
Correct answer: Neutrons
Nuclear fission releases free neutrons along with energy and smaller nuclei. These neutrons can strike other nuclei and trigger additional fission reactions, creating a chain reaction.
Which scientist proposed the famous equation E = mc² that explains nuclear energy?
- A Isaac Newton
- B Albert Einstein
- C Niels Bohr
- D Ernest Rutherford
Correct answer: Albert Einstein
Albert Einstein introduced the equation E = mc², which states that mass can be converted into energy. This principle explains why nuclear reactions release enormous amounts of energy.