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Physics
Dec 12, 2025
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Sophieeee ๐๐๐๐บ๐ @sophiesnotes
Half-life Calculations and Radiation Safety Guide- A comprehensive guide covering numerical and graphical methods for calculating half-life,... Show more
This section explains how to calculate half-life from a graph in chemistry and physics.
The process involves
Example Using a graph of count rate vs. time, the half-life is determined to be 1.2 hours by analyzing multiple pairs of points.
Highlight When selecting points, choose those that land nearly on exact values for more accurate results.
This page outlines an experiment to measure the half-life of a radioactive material, which is essential for understanding how to measure half-life of radioactive material experimentally.
Key steps in the experiment include
Highlight It's crucial to measure and subtract background radiation to get accurate results.
This section introduces the concept of dosimetry and absorbed dose in nuclear physics.
Definition Absorbed dose is the energy absorbed per unit mass of the absorbing material.
Key points
Example A person undergoing hospital treatment where an organ of mass 250g absorbs 20J of energy receives an absorbed dose of 80 Gy.
Highlight The absorbed dose is higher if the energy is concentrated on a smaller mass of tissue.
This page expands on dosimetry by introducing the concept of equivalent dose.
Definition Equivalent dose is a measure of the biological effect of radiation, taking into account radiation type, absorbed dose, and exposed body organs or tissue.
Key points
Example A worker in a nuclear power station receiving 10 mGy of slow neutrons and 2.5 mGy of gamma rays in a year has a total equivalent dose of 0.055 Sv.
Highlight Equivalent dose provides a more accurate representation of radiation's biological effects compared to absorbed dose alone.
This final section explores the practical applications of dosimetry in various fields, emphasizing its importance in radiation protection and medical physics.
Key applications of dosimetry include
Radiation Protection in Nuclear Facilities
Medical Imaging
Radiation Therapy
Environmental Monitoring
Space Exploration
Highlight Accurate dosimetry is crucial in maintaining the ALARA principle (As Low As Reasonably Achievable) in radiation protection.
Example In radiation therapy, dosimetrists use sophisticated planning systems to calculate the optimal radiation dose distribution, ensuring that the tumor receives the prescribed dose while minimizing exposure to surrounding healthy tissues.
Understanding and applying dosimetry principles is essential for professionals working in radiation-related fields, ensuring the safe and effective use of ionizing radiation in various applications.
Page 7 Equivalent Dose in Radiation Protection
This section covers equivalent dose calculations and radiation weighing factors.
Formula Equivalent Dose = Absorbed Dose ร Radiation Weighing Factor
Vocabulary Sievert (Sv) - unit for equivalent dose Gray (Gy) - unit for absorbed dose
Example Calculation of total equivalent dose for a nuclear power station worker exposed to multiple radiation types.
Page 8
Page 8 Dosimetry Rates and Calculations
Covers the calculation of dose rates and practical applications in radiation safety.
Example Calculating equivalent dose rate for a radiation worker exposed to 120 ยตSv over a working week.
Formula Absorbed dose rate = Absorbed Dose / Time
This section introduces the concept of half-life and demonstrates how to calculate it numerically.
Definition The half-life of a radioactive source is the time taken for the activity to fall to half its previous value.
The page covers three main types of problems
Finding Initial Activity Given the current activity and half-life, calculate the activity at a previous time.
Finding Final Activity Given the initial activity and half-life, determine the activity after a specific time period.
Finding Half-Life Given initial and final activities over a time period, calculate the half-life.
Example A source with an activity of 1024 Bq and a half-life of 3 days will have an activity of 32 Bq after 15 days.
Highlight Always start calculations from time zero and halve the activity for each half-life period.
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
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Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
This note sheet can be used for high school students taking physics classes to study for finals, unit tests, and review.
PhysicsThey only contain the topics from physics P1
PhysicsRadio waves, microwaves, infrared, visible lights, ultraviolet, x-ray, gamma.
Physicsforce and motion revision
PhysicsExplore key concepts in physics including contact and non-contact forces, elasticity, moments, fluid pressure, wave types, and the life cycle of stars. This summary provides essential formulas and principles for understanding motion, energy transfer, and the behavior of light. Ideal for foundation physics revision.
PhysicsPHYSICAL SCIENCE NOTES, LAB EQUIPMENT
PhysicsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think itโs very much worth it and youโll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still donโt get it!!! In the end I think itโs worth it ๐๐ โ ๏ธAlso DID I MENTION ITS FREEE YOU DONโT HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLYโ๏ธโ๏ธโ ๏ธ
Thomas R
iOS user
Knowunity is the BEST app Iโve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help๐ค๐ค
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.๐๐ฉท๐
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as Iโve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think itโs very much worth it and youโll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still donโt get it!!! In the end I think itโs worth it ๐๐ โ ๏ธAlso DID I MENTION ITS FREEE YOU DONโT HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLYโ๏ธโ๏ธโ ๏ธ
Thomas R
iOS user
Knowunity is the BEST app Iโve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help๐ค๐ค
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.๐๐ฉท๐
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as Iโve seen! Geometry too!
Paul T
iOS user
Sophieeee ๐๐๐๐บ๐
@sophiesnotes
Half-life Calculations and Radiation Safety Guide - A comprehensive guide covering numerical and graphical methods for calculating half-life, experimental procedures, and radiation safety measures.
Key Points:
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section explains how to calculate half-life from a graph in chemistry and physics.
The process involves:
Example: Using a graph of count rate vs. time, the half-life is determined to be 1.2 hours by analyzing multiple pairs of points.
Highlight: When selecting points, choose those that land nearly on exact values for more accurate results.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page outlines an experiment to measure the half-life of a radioactive material, which is essential for understanding how to measure half-life of radioactive material experimentally.
Key steps in the experiment include:
Highlight: It's crucial to measure and subtract background radiation to get accurate results.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section introduces the concept of dosimetry and absorbed dose in nuclear physics.
Definition: Absorbed dose is the energy absorbed per unit mass of the absorbing material.
Key points:
Example: A person undergoing hospital treatment where an organ of mass 250g absorbs 20J of energy receives an absorbed dose of 80 Gy.
Highlight: The absorbed dose is higher if the energy is concentrated on a smaller mass of tissue.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page expands on dosimetry by introducing the concept of equivalent dose.
Definition: Equivalent dose is a measure of the biological effect of radiation, taking into account radiation type, absorbed dose, and exposed body organs or tissue.
Key points:
Example: A worker in a nuclear power station receiving 10 mGy of slow neutrons and 2.5 mGy of gamma rays in a year has a total equivalent dose of 0.055 Sv.
Highlight: Equivalent dose provides a more accurate representation of radiation's biological effects compared to absorbed dose alone.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This final section explores the practical applications of dosimetry in various fields, emphasizing its importance in radiation protection and medical physics.
Key applications of dosimetry include:
Radiation Protection in Nuclear Facilities:
Medical Imaging:
Radiation Therapy:
Environmental Monitoring:
Space Exploration:
Highlight: Accurate dosimetry is crucial in maintaining the ALARA principle (As Low As Reasonably Achievable) in radiation protection.
Example: In radiation therapy, dosimetrists use sophisticated planning systems to calculate the optimal radiation dose distribution, ensuring that the tumor receives the prescribed dose while minimizing exposure to surrounding healthy tissues.
Understanding and applying dosimetry principles is essential for professionals working in radiation-related fields, ensuring the safe and effective use of ionizing radiation in various applications.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Page 7: Equivalent Dose in Radiation Protection
This section covers equivalent dose calculations and radiation weighing factors.
Formula: Equivalent Dose = Absorbed Dose ร Radiation Weighing Factor
Vocabulary: Sievert (Sv) - unit for equivalent dose Gray (Gy) - unit for absorbed dose
Example: Calculation of total equivalent dose for a nuclear power station worker exposed to multiple radiation types.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Page 8:
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Page 8: Dosimetry Rates and Calculations
Covers the calculation of dose rates and practical applications in radiation safety.
Example: Calculating equivalent dose rate for a radiation worker exposed to 120 ยตSv over a working week.
Formula: Absorbed dose rate = Absorbed Dose / Time
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section introduces the concept of half-life and demonstrates how to calculate it numerically.
Definition: The half-life of a radioactive source is the time taken for the activity to fall to half its previous value.
The page covers three main types of problems:
Finding Initial Activity: Given the current activity and half-life, calculate the activity at a previous time.
Finding Final Activity: Given the initial activity and half-life, determine the activity after a specific time period.
Finding Half-Life: Given initial and final activities over a time period, calculate the half-life.
Example: A source with an activity of 1024 Bq and a half-life of 3 days will have an activity of 32 Bq after 15 days.
Highlight: Always start calculations from time zero and halve the activity for each half-life period.
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help โ all at your fingertips.
3
Smart Tools NEW
Transform this note into: โ 50+ Practice Questions โ Interactive Flashcards โ Full Mock Exam โ Essay Outlines
This note sheet can be used for high school students taking physics classes to study for finals, unit tests, and review.
PhysicsThey only contain the topics from physics P1
PhysicsRadio waves, microwaves, infrared, visible lights, ultraviolet, x-ray, gamma.
Physicsforce and motion revision
PhysicsExplore key concepts in physics including contact and non-contact forces, elasticity, moments, fluid pressure, wave types, and the life cycle of stars. This summary provides essential formulas and principles for understanding motion, energy transfer, and the behavior of light. Ideal for foundation physics revision.
PhysicsPHYSICAL SCIENCE NOTES, LAB EQUIPMENT
PhysicsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think itโs very much worth it and youโll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still donโt get it!!! In the end I think itโs worth it ๐๐ โ ๏ธAlso DID I MENTION ITS FREEE YOU DONโT HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLYโ๏ธโ๏ธโ ๏ธ
Thomas R
iOS user
Knowunity is the BEST app Iโve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help๐ค๐ค
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.๐๐ฉท๐
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as Iโve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think itโs very much worth it and youโll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still donโt get it!!! In the end I think itโs worth it ๐๐ โ ๏ธAlso DID I MENTION ITS FREEE YOU DONโT HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLYโ๏ธโ๏ธโ ๏ธ
Thomas R
iOS user
Knowunity is the BEST app Iโve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help๐ค๐ค
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.๐๐ฉท๐
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH ๐๐๐ฒ๐ค๐โจ๐๐ฎ
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as Iโve seen! Geometry too!
Paul T
iOS user
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