Photo AI
Radon is a radioactive gas which is present in some rocks - Leaving Cert Physics - Question 12 - 2015
Question 12
Radon is a radioactive gas which is present in some rocks. It can sometimes build up in houses and cause health concerns. What is meant by the term radioactive? (6)... show full transcript
Worked Solution & Example Answer:Radon is a radioactive gas which is present in some rocks - Leaving Cert Physics - Question 12 - 2015
Step 1
What is meant by the term radioactive?
Answer
The term 'radioactive' refers to the spontaneous disintegration of a nucleus, which leads to the emission of radiation. This process occurs when unstable atomic nuclei lose energy by emitting radiation in the form of particles or electromagnetic waves.
Step 2
Name a detector of radiation and describe, with the aid of a labelled diagram, its principle of operation.
Answer
A common detector of radiation is the Geiger-Müller (GM) tube. The GM tube consists of a cathode and anode within a low-pressure inert gas environment.
Diagram Description:
- Cathode: The outer casing of the tube.
- Anode: Thin wire located in the center, which is positively charged.
- Gas: Low-pressure inert gas, such as argon.
Principle of Operation:
When radiation enters the tube, it ionizes the gas, producing free electrons and holes. These charged particles then accelerate towards the anode and cathode, resulting in an electrical pulse that can be detected and counted.
Step 3
How many radon-210 atoms will remain after one day?
Answer
To calculate the number of radon-210 atoms remaining after one day, we begin with the initial amount of atoms and apply the decay formula. The half-life of radon-210 is 144 minutes, allowing us to determine how many half-lives fit into one day.
Steps:
-
Convert one day to minutes: 1 day = 1440 minutes.
-
Calculate the number of half-lives:
egin{align*} ext{Number of Half-lives} &= \frac{1440 ext{ minutes}}{144 ext{ minutes/half-life}} = 10 ext{ half-lives} egin{align*}
-
Apply the decay formula:
ext{Remaining atoms} = N_0 \left(\frac{1}{2}\right)^n ext{Where: } N_0 = 4.5 \times 10^5, n = 10\n ext{Remaining atoms} = 4.5 \times 10^5 \left(\frac{1}{2}\right)^{10} = 4.5 \times 10^5 \left(\frac{1}{1024}\right) \approx 4.4 \times 10^3
Thus, approximately 4.4 × 10^3 radon-210 atoms will remain after one day.