Radioactivity Lecture 2
47 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What particles are β-particles identical to?

  • Electrons (correct)
  • Neutrons
  • Protons
  • Alpha particles

Which particle has the highest penetrating power?

  • Beta particles
  • Alpha particles
  • X-rays
  • Gamma rays (correct)

How does the ionising power of β-particles compare to α-particles?

  • Less than that of γ-rays
  • Equal to α-particles
  • More than α-particles
  • One-hundredth of that of α-particles (correct)

What is the primary reason γ-rays are considered weak ionisers?

<p>The chances of photon-electron collisions are small (B)</p> Signup and view all the answers

What thickness of aluminum can stop β-particles?

<p>1 cm (A)</p> Signup and view all the answers

Which of the following statements is true about α-particles?

<p>They can ionize gas more intensely than β-particles (A)</p> Signup and view all the answers

What characteristic differentiates gamma rays from alpha and beta rays?

<p>Gamma rays are a form of electromagnetic radiation (C)</p> Signup and view all the answers

Which particle travels about 10 times faster than α-particles?

<p>Beta particles (C)</p> Signup and view all the answers

What is the nature of an α-particle?

<p>He nucleus (A)</p> Signup and view all the answers

Which type of radiation has the highest penetrating power?

<p>ϒ -- rays (D)</p> Signup and view all the answers

What material can effectively stop α-particles?

<p>Paper or 0.01mm thick Al sheet (D)</p> Signup and view all the answers

Which technique is primarily used to visualize the tracks of α or β particles?

<p>Cloud Chamber (D)</p> Signup and view all the answers

What primarily happens when radiation passes through an ionization chamber?

<p>It ionizes gas molecules, forming positive ions and electrons (B)</p> Signup and view all the answers

How does the Geiger-Muller counter detect radiation?

<p>By detecting the movement of argon ions to the cathode (D)</p> Signup and view all the answers

What is the primary function of a Cloud Chamber in radioactivity studies?

<p>To provide detailed snapshots of particle paths (A)</p> Signup and view all the answers

Which device is specifically used to measure the rate of emission of α- or β-particles?

<p>Geiger-Muller Counter (B)</p> Signup and view all the answers

What role does the scintillation counter serve in detecting radiation?

<p>It produces electrical pulses in response to scintillations. (C)</p> Signup and view all the answers

What is one limitation of the film badge in detecting radiation?

<p>It does not accurately measure ϒ-radiation intensity. (D)</p> Signup and view all the answers

What type of radiation does a film badge specifically track?

<p>Both α- and β-particles. (D)</p> Signup and view all the answers

Which component in a modern scintillation counter replaces the zinc sulphide screen?

<p>A crystal of sodium iodide with thallium iodide. (D)</p> Signup and view all the answers

How often should the film badge be developed to monitor radiation exposure?

<p>Periodically based on exposure levels. (A)</p> Signup and view all the answers

What does the electrical pulse measured by a scintillation counter correspond to?

<p>The number of scintillations detected. (A)</p> Signup and view all the answers

What is a key feature of radioactive decay according to Rutherford and Soddy's theory?

<p>It involves the emission of α- or β-particles. (B)</p> Signup and view all the answers

What is the benefit of using a scintillation counter over a spinthariscope?

<p>It can count a greater number of particles per second. (C)</p> Signup and view all the answers

What is the result of α-decay on the atomic mass of the parent nucleus?

<p>Decreases by 4 (C)</p> Signup and view all the answers

Which of the following correctly describes the process of β-decay?

<p>A neutron converts into a proton and emits a β-particle. (A)</p> Signup and view all the answers

What is the relationship between the parent nucleus and the daughter nucleus after α-decay?

<p>The daughter nucleus has a lower atomic mass and atomic number. (D)</p> Signup and view all the answers

If a parent nucleus has an atomic mass of 232 and undergoes 6 α-emissions, what will be its final atomic mass?

<p>204 (D)</p> Signup and view all the answers

What happens to the atomic mass of the nucleus during β-decay?

<p>Remains unchanged (D)</p> Signup and view all the answers

Which of the following nuclei will have the same mass number but different atomic numbers after one β-emission?

<p>Lead-214 and Bismuth-214 (C)</p> Signup and view all the answers

What type of nucleus is formed when a radioactive element undergoes one α-emission and two β-emissions?

<p>Isotopic nucleus (B)</p> Signup and view all the answers

What instrument is commonly used to determine the activity of a radioactive sample?

<p>Geiger-Muller counter (C)</p> Signup and view all the answers

How can the half-life of an isotope be calculated?

<p>By using the decay constant in a specific equation (C)</p> Signup and view all the answers

What is the rate of decay equal to in a radioactive sample?

<p>The rate of emission of alpha particles (D)</p> Signup and view all the answers

What is the decay constant represented as mathematically in the equations?

<p>λ (A)</p> Signup and view all the answers

If cobalt-60 has a half-life of 5.2 years, what can be inferred about its decay over time?

<p>It will retain exactly half of its atoms after 5.2 years (C)</p> Signup and view all the answers

What is the activity of radon related to its mass in disintegrations per second?

<p>It is equal to the number of atoms disintegrating per second (A)</p> Signup and view all the answers

Which of the following correctly describes the amount of sample left after a given time?

<p>It can be calculated using the initial sample amount and the decay constant. (A)</p> Signup and view all the answers

What is the significance of the relationship between N0 and N in radioactive decay?

<p>It indicates the fraction of the original sample remaining. (B)</p> Signup and view all the answers

What percentage of a cobalt-60 sample remains after 15 years if the disintegration constant is 0.13 yr^-1?

<p>14% (A)</p> Signup and view all the answers

How long does it take for a sample of cobalt-60 to decay to only 2.0 percent of its original amount?

<p>30 years (A)</p> Signup and view all the answers

What is the half-life of a radioactive isotope if it can decay from an initial amount to 1.25g after 40 days starting from 5g?

<p>20 days (D)</p> Signup and view all the answers

How much time is required for a radioactive sample with a half-life of 33 minutes to lose one-third of its atoms?

<p>19.31 minutes (B)</p> Signup and view all the answers

What is the remaining fraction N/N₀ of a radioactive isotope after one hour if its half-life is 47.2 seconds?

<p>1.12 x 10^-23 (C)</p> Signup and view all the answers

What is defined as the conversion of one element to another by a nuclear change?

<p>Transmutation (B)</p> Signup and view all the answers

What is the primary outcome of a nuclear reaction?

<p>Creation of a new atom with a different atomic number (A)</p> Signup and view all the answers

In the context of nuclear reactions, what does the term 'nuclear transmutation' refer to?

<p>Artificial changes to atomic nuclei (A)</p> Signup and view all the answers

Flashcards

Beta Particle Velocity

About 10 times faster than alpha particles but same as light.

Beta Particles

Streams of electrons emitted by a nucleus.

Beta Particle Penetration

100 times more penetrating than alpha particles

Beta Particle Ionization

Much lower than alpha particles.

Signup and view all the flashcards

Gamma Rays

Electromagnetic radiation of shorter wavelength than X-rays.

Signup and view all the flashcards

Gamma Ray Velocity

Travel at the speed of light.

Signup and view all the flashcards

Gamma Ray Ionization

Very weak compared to others

Signup and view all the flashcards

Gamma Ray Penetration

High penetration, requires thick material to stop.

Signup and view all the flashcards

Alpha particle nature

An alpha particle is a helium nucleus.

Signup and view all the flashcards

Beta particle nature

A beta particle is a high-speed electron.

Signup and view all the flashcards

Gamma rays nature

Gamma rays are a form of high-energy electromagnetic radiation.

Signup and view all the flashcards

Alpha particle penetration

Alpha particles have low penetrating power.

Signup and view all the flashcards

Cloud chamber use

Detects radiation by creating visible tracks through water vapor or liquid hydrogen.

Signup and view all the flashcards

Ionization chamber function

Measures the strength of radiation by detecting ionization of gas.

Signup and view all the flashcards

Radioactive Decay

A process where an unstable atomic nucleus spontaneously emits an α or β particle.

Signup and view all the flashcards

Scintillation Counter

A device that measures radioactivity by detecting flashes of light (scintillations) produced when radiation strikes a special material.

Signup and view all the flashcards

Film Badge

A device for monitoring radiation exposure, using photographic film that darkens in proportion to the radiation.

Signup and view all the flashcards

Radioactivity Intensity

The rate of radioactive emissions in a material, usually measured in pulses per minute.

Signup and view all the flashcards

Alpha and Beta Particles

Subatomic particles emitted during radioactive decay processes.

Signup and view all the flashcards

Nuclear Property

Radioactivity is a characteristic of the atomic nucleus, not the atom's electrons.

Signup and view all the flashcards

Spontaneous Emission

Radioactivity happens automatically, or without outside intervention.

Signup and view all the flashcards

Automatic Counter

A device automatically counts the number of electrical pulses, representing the number of particles emitted.

Signup and view all the flashcards

Parent Nucleus

The original nucleus before radioactive decay.

Signup and view all the flashcards

Daughter Nucleus

The nucleus formed after radioactive decay.

Signup and view all the flashcards

Alpha Decay

Radioactive decay process where an alpha particle is emitted from the nucleus.

Signup and view all the flashcards

Alpha Particle

A particle consisting of two protons and two neutrons, essentially a helium nucleus.

Signup and view all the flashcards

Beta Decay

Radioactive decay process where a beta particle is emitted from the nucleus.

Signup and view all the flashcards

Isobar

Nuclei that have the same mass number but different atomic numbers.

Signup and view all the flashcards

Isotope

Atoms of the same element that have the same atomic number but different mass numbers.

Signup and view all the flashcards

Geiger-Muller Counter

A device used to measure the activity of radioactive samples by detecting ionizing radiation.

Signup and view all the flashcards

Half-life

The time it takes for half of the radioactive nuclei in a sample to decay.

Signup and view all the flashcards

Decay Constant (λ)

A measure of how quickly a radioactive substance decays, representing the probability of a single nucleus decaying per unit time.

Signup and view all the flashcards

Calculate Half-life

To determine the half-life of a radioactive substance using the formula t1/2 = 0.693/λ, where λ is the decay constant.

Signup and view all the flashcards

Activity of a Sample

The rate at which radioactive nuclei decay, measured in disintegrations per second (dps) or becquerels (Bq).

Signup and view all the flashcards

Calculate Activity

To determine the activity of a radioactive sample using the formula Activity = λN, where λ is the decay constant and N is the number of radioactive nuclei.

Signup and view all the flashcards

Amount Remaining After Time t

The amount of radioactive substance left after a certain time can be calculated using the formula N = N0e^(-λt), where N0 is the initial amount, λ is the decay constant, and t is the elapsed time.

Signup and view all the flashcards

Fraction of Sample Remaining

The ratio of the amount of radioactive substance remaining after time t to the initial amount, expressed as a fraction or percentage.

Signup and view all the flashcards

What is radioactive decay?

A process where an unstable atomic nucleus releases energy and particles to become more stable.

Signup and view all the flashcards

What is a disintegration constant?

The probability that a nucleus of a radioactive isotope will decay per unit time.

Signup and view all the flashcards

What is half-life?

The time taken for half of the radioactive nuclei in a sample to decay.

Signup and view all the flashcards

What is transmutation?

The conversion of one element into another by a nuclear reaction.

Signup and view all the flashcards

What is a nuclear reaction?

A reaction involving the nucleus of an atom where the number of protons and neutrons changes.

Signup and view all the flashcards

What is the difference between a chemical reaction and a nuclear reaction?

Chemical reactions involve rearranging electrons outside the nucleus, while nuclear reactions involve changes within the nucleus.

Signup and view all the flashcards

How is the fraction remaining after a radioactive decay calculated?

The remaining fraction is the amount at a given time divided by the initial amount.

Signup and view all the flashcards

How can the age of an artifact be determined using radioactive decay?

By measuring the ratio of radioactive isotopes in the artifact compared to a reference sample, the age can be estimated based on the known half-life.

Signup and view all the flashcards

Study Notes

Radioactivity (Lecture 2)

  • A nuclear reaction differs from a chemical reaction as it involves changes in the atom's nucleus, whereas a chemical reaction involves rearranging extra-nuclear electrons.
  • Nuclear chemistry studies changes in the nucleus of atoms, altering proton or neutron numbers, thereby forming new elements.
  • Some elements, like uranium and radium, are unstable. Their nuclei spontaneously break down, releasing excess particles and energy, which is called radiation.
  • Radioactive disintegration or decay is the spontaneous breaking down of unstable atoms. This process releases radiation, which characterizes radioactive elements.

Types of Radiations

  • Radioactive radiations are categorized into three types.
  • Rutherford sorted these radiations by passing them through electrically charged plates.
  • Alpha (α) rays are positively charged and deflected towards the negative plate.
  • Beta (β) rays are negatively charged and deflected towards the positive plate.
  • Gamma (γ) rays are uncharged and pass straight through the electric field.

Properties of Alpha, Beta, and Gamma Rays

  • Alpha (α), beta (β), and gamma (γ) rays exhibit different properties.
    • Velocity: Alpha particles are the slowest; beta particles are faster than alpha particles; gamma rays travel at the speed of light.
    • Penetrating power: Gamma rays are highly penetrating; beta particles have moderate penetration; alpha particles have the lowest penetrating power.
    • Ionisation: Alpha particles cause the most ionization; beta particles cause less ionization than alpha particles; gamma rays have the least ionization.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Radioactivity (Lecture 2) PDF

Description

This quiz covers Lecture 2 on Radioactivity, focusing on the differences between nuclear and chemical reactions, the study of nuclear chemistry, and the types of radioactive radiations. It explores radioactive decay and the characteristics of unstable elements. Test your understanding of these fundamental concepts of radioactivity!

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser