half life, for my physics but pretty sure it involves maths. you don’t have to do them all i’m just confused how to work it out.
Answers
I probably don't have to tell you that the other answer is nonsense, but I'll do it all the same, just in case... Half-life is defined as the time it takes for some radioactive substance to decay to half its original amount.
If it takes n half-lives for some substance with a starting amount of A to decay to a final amount of B, then
[tex]B = \dfrac{A}{2^n}[/tex]
1. If the half-life is x, then after 1 half-life, 5000 units of this substance decays to 2500 units. After another half-life, this decays to 1250. After another, this in turn decays to 625.
So 3 half-lives are required.
In terms of the equation above, we solve for n such that
[tex]625 = \dfrac{5000}{2^n} \implies 2^n = 8 \implies n=3[/tex]
since 2³ = 8.
2. Count how many times you halve 15,000 to end up with 3750:
15,000/2 = 7500
7500/2 = 3750
===> 2 half-lives
In other words,
[tex]3750 = \dfrac{15,000}{2^n} \implies 2^n = 4 \implies n=2[/tex]
3. After 1 half-life, you would end up with
12,000/2 = 6000
and after another half-life,
6000/2 = 3000
i.e.
[tex]\dfrac{12,000}{2^2} = \dfrac{12,000}4 = 3000[/tex]
4. After 1 half-life, you have
26,000/2 = 13,000
After 2 half-lives,
13,000/2 = 6500
After 3 half-lives,
6500/2 = 3250
After 4 half-lives,
3250/2 = 1625
i.e.
[tex]\dfrac{26,000}{2^4} = \dfrac{26,000}{16} = 1625[/tex]
5. If the half-life is 3 years, then 15 years = 3 half-lives.
In the last 3 years, 20,000 would have decayed to 10,000.
In the second-to-last 3 years, 40,000 would have decayed to 20,000.
In the first 3 years, 80,000 would have decayed to 40,000.
i.e.
[tex]\dfrac{x}{2^3} = 10,000 \implies x = 8\times10,000 = 80,000[/tex]
Related Questions
Explain
(0) what is meant by regeneration,
(ii) why an analogue signal cannot be regenerated
Answers
Explanation:
1.) Regeneration is the natural process of replacing or restoring damaged or missing cells, tissues, organs, and even entire body parts to full function in plants and animals.2.) When noise is added to analogue signals, it usually sounds like background hiss. Such noise can not be removed so the original clean signal can not be re-created or re-generated.
A 50kg gymnast is bouncing on a trampoline. If she is going down at 5m/s when she lands on the trampoline, and it bouncesher up in the opposite direction at a velocity of 4m/s, whatis her change in momentum?
Answers
Answer:
450 kgm/s upward
Explanation:
From the question,
Change in monentum = mass× change in velocity
ΔM = mΔv....................... Equation 1
ΔM = m(v-u).................. Equation 2
Where ΔM = Change in momentum, m = mass of the gymnast, v = final velocity, u = initial velocity
Given: m = 50 kg, v = -4 m/s. u = 5 m/s
Substitute these values into equation 2
ΔM = 50(-4-5)
ΔM = 50(-9)
ΔM = -450 kgm/s
Hence the change in momentum of the gymnast is 450 kgm/s upward
HELP PLEASE!! GIVING BRAINLIEST!! If you answer this correctly ill answer some of your questions you have posted! (20pts)
Answers
Explanation:
potential energy =360800J
mass(m)=?
height (h)=25m
g=9.8m/s²
we have
potential energy =360800J
mgh=360800J
m×9.8×25=360800
m=360800/(9.8×25)=1472.653061kg
Answer:
HELP PLEASE!! GIVING BRAINLIEST!! If you answer this correctly ill answer some of your questions you have posted!
William drew a diagram of a box containing a gas for his science project. His drawing is shown.
Answers
What do you hope to learn from participating in the activity you selected?
Answers
For example
If you participated in a cooking activity you will always be looking to learn cooking skills and abilities.
Answer:
I hope to learn the basic moves and stances of boxing. I understand that I won't be boxing with another person, but that’s OK. These exercises seem like a good starting point. I really want to understand how to put together combinations. I’ve seen professional boxers throw combinations on TV, but their hands move so quickly that I can’t catch the finer details of the sport. Maybe this will be an opportunity for me to find out more.
Explanation:
17) An object is being pulled in two different directions by two students. One student pulls to the left with 12 N
and the other pulls to the right with 15 N. What is the net force on the object?
a) 27 N right.
b) 3 N right
c) 2 N left.
d) 3 N left.

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number of atoms of each element Sulfur dioxide?
Answers
Answer:
Element Symbol # of Atoms
Oxygen O 2
Sulfur S 1
Explanation:
8. List the objects in order from least to greatest inertia
A
B
D
5 kg
4 kg
3 kg
10 kg
a = 1 m/s/s
a 3 m/s/s
a 2 miss
a= 0 m/s/s
Answers
Answer:
mhibyguftyftfrehlknmjhbn
Explanation:
njhvvtfryvbnyuhnuihnjhk
The offspring resulting from sexual reproduction are exactly like their parents.
false
true
Answers
Answer:
false
Explanation:
As both parents contribute half of the new organism's genetic material, the offspring will have traits of both parents, but will not be exactly like either parent
Answer:
False
Explanation:
The only time you end up like your parent is asexual reproduction
If an owl produces two pellets every 24 hours and each pellet contains the remains of 3 prey, how much does it eat in a week? A month?
Answers
A month (assuming it’s 30 days)=1,260 prey
The owl eats 42 prey in a week and 180 prey in a month.
To calculate how much the owl eats in a week and a month, we need to determine the number of prey consumed in each time period.
In a week:
The owl produces two pellets every 24 hours. So, in one day, it consumes 2 * 3 = 6 prey (since each pellet contains the remains of 3 prey).
In a week (7 days), the owl consumes 6 * 7 = 42 prey.
In a month:
Assuming a month has 30 days (though some months have 31 days or 28/29 days), we can calculate the number of prey consumed in a month.
In a day: 6 prey
In a month (30 days): 6 * 30 = 180 prey.
Hence, the owl eats 42 prey in a week and 180 prey in a month.
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A long solenoid that has 920 turns uniformly distributed over a length of 0.380 m produces a magnetic field of magnitude 1.00 10-4 T at its center. What current is required in the windings for that to occur?
Answers
Answer: 0.0328 A
Explanation:
Given
No of turns [tex]N=920[/tex]
Length of solenoid [tex]L=0.380\ m[/tex]
Magnetic field [tex]B=10^{-4}\ T[/tex]
the magnetic field at the center of the solenoid is
[tex]\Rightarrow B=\mu nI=\mu \dfrac{N}{L}I[/tex]
Putting values we get
[tex]\Rightarrow 10^{-4}=4\pi \times 10^{-7}\times \dfrac{920}{0.380}\times I\\\\\Rightarrow I=\dfrac{0.380\times 1000}{920\times 4\pi}=0.0328\ A[/tex]
What's the name of the compound Cal2?
Answers
Answer:
The correct answer is calcium iodide.
Explanation:
Hope this helped Mark BRAINLIEST!!!
The compound with the chemical formula CaI₂ is called calcium iodide.
A compound is a substance formed when two or more elements chemically combine in specific proportions. It is characterized by a distinct chemical composition and properties that differ from the elements it is composed of. Compounds are held together by chemical bonds, which can be either ionic or covalent, depending on the nature of the elements involved.
Calcium Iodide (CaI₂):
Calcium iodide is an ionic compound composed of the elements calcium (Ca) and iodine (I). In this compound, calcium, which is a metal, donates two electrons to iodine, a non-metal, resulting in the formation of a calcium ion (Ca²⁺) and two iodide ions (I⁻). The ions are held together by electrostatic forces of attraction, forming a crystal lattice structure.
Calcium iodide is a white, crystalline solid that is highly soluble in water. It is commonly used in various applications, including as a catalyst in organic reactions, a source of iodine for nutritional supplements, and in the synthesis of pharmaceuticals.
Therefore, The correct answer is Calcium Iodide.
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HELPP ME IN PHYSICS +15 POINTS!!
But a right answer not links or I’ll report. -_-
Answers
The answer shud be 31 . 14m
Explain what ionisation is and why it is dangerous
Answers
Ionisation: the loss or gain of an electron
It is dangerous because cells that have been ionised can either die, or can mutate incorrectly, which might cause cancer.
Help Please!!!!!!!!!!!!!!!!!!
Answers
(True/False) The normal force is always opposite in direction to weight.
Answers
Answer:
True
Explanation:
Explain how air exerts a pressure
Answers
air exert a pressure take a glass and put the water on it and small piece a paper and glass take downword and observe it so tha air exert pressure
A 0.40 kg soccer ball has 20 J of kinetic energy. How fast is it moving?
Answers
1/2 x 0,40 x v^2 = 20J
v^2 = 20/0,5x0,4
v^2 = 100
v = 10
it is moving at 10 m/s
What happens when cooler downdrafts inside a supercell move across the edge of an upward moving mesocyclone?
A. A supercell
B. A me so cyclone
C. A tornado
D. A hurricane
Answers
If the area of a concrete slap weighing 300n is 400cm2 ,how much pressure can it apply when kept on the ground
Answers
Answer:
7500 N/m²
Explanation:
From the question given above, the following data were obtained:
Force (F) = 300 N
Area (A) = 400 cm²
Pressure (P) =?
Next, we shall convert 400 cm² to m². This can be obtained as follow:
1×10⁴ cm² = 1 m²
Therefore,
400 cm² = 400 cm² × 1 m² / 1×10⁴ cm²
400 cm² = 0.04 m²
Finally, we shall determine the pressure. This can be obtained as follow:
Force (F) = 300 N
Area (A) = 0.04 m²
Pressure (P) =?
P = F/A
P = 300 / 0.04
P = 7500 N/m²
HELP!!! I MIGHT FAIL THE 6th GRADE IF I DON'T GET HELP!!!! The southern United States experiences periodic occurrences of severe cold and drought conditions. Which weather phenomenon most likely causes this and why?
Answers
Answer:
La Niña, because the jet stream is displaced northwards
Explanation:
La Nina is known to be a cool phase that affects the average ocean temperature. During this period the surface wind becomes stronger and there is lesser rainfall over the areas of the central tropical Pacific to which the Southern United States belongs.
Hence, when the southern United States experiences periodic occurrences of severe cold and drought conditions, the weather phenomenon most likely causes this and why is "La Niña, because the jet stream is displaced northwards."
Two magnets are attracting each other. One magnet is big and strong; the other is small and weak. The big magnet attracts the small magnet with:
Answers
Answer:
magnetism and dipole-dipole interaction
Explanation:
Two magnets are attracting each other, one magnet is big and strong, the other is small and weak, the big magnet attracts the small magnet with a stronger force, and the attraction depends on the size of the magnet.
What is the significance of the magnet and magnetic fields?The attraction between two magnets varies, and that depends upon several factors such as the strength of the force of attraction, which determines the usefulness and functionality of magnets, for example, in industrial settings, strong magnets are often used to lift heavy loads, etc.
Hence, two magnets are attracting each other, one magnet is big and strong, the other is small and weak, the big magnet attracts the small magnet with a stronger force, and the attraction depends on the size of the magnet.
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What is the difference between the law of gravity and the theory of gravity?
Answers
Answer:
In the language of science, a theory is an explanation of why and how things happen. For gravity, we use Einstein's Theory of General Relativity to explain why things fall. ...While laws rarely change, theories change frequently as new evidence is discoevered.
answer this plsss
A mobile phone operates at 900 MHz.
What wavelength does it use?
Answers
Answer:
The wavelength = 0.3333 meters at 900 MHz, therefore, = /4 = 0.08333 meters.
(20 points) What are wispy looking clouds, usually at high altitudes called?
stratus clouds
nimbus clouds
cirrus clouds
cumulus clouds
Answers
Answer:
the answer is c cirrus clouds
Explanation:
An airplane is cruising at a speed of 250 m/s. If the airplanes engines provide a forward force of 19,540 N, calculate the force of the air resistance (friction) that is acting on the plane.
Answers
If a force is applied to an object, which of the following must be true?
Answers
Answer:
D. The force applied will contribute to the total net force.
good luck, i hope this helps :)
Describe 3 physical properties of this object (color, state of matter, shape, size, hardness, etc)
Answers
Answer: The color is orange, the state of matter is liquid
Explanation:
what is SI unit of speed
Answers
Answer:
m/s
Explanation:
The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour.
m/s
which is also written as
ms-¹
The above mentioned symbols are said as 'meter per second'
hope it helps!
Two charges of 5 x 10-6 C are a certain distance apart. These two positive charges experience 3.6 N of repelling electrical force between them. How far apart are these charges?
Answers
Answer:
r = 0.2499 m
Explanation:
Use Coulomb's Law: [tex]F_{e} = kq_{1}q_{2} / r^{2}[/tex] where Fe is the electric force, q1 and q2 are the 2 charges respectively, k is a constant (8.99*10^9 N • m^2 / C^2) and r is the distance.
[tex]3.6 N = (8.99*10^{9})(5*10^{-6})(5*10^{-6}) / r^{2}[/tex]
r = 0.2499 m
The distance that should be apart from these charges should be considered when the r = 0.2499 m.
Calculation of the distance apart:Since
Two charges of 5 x 10-6 C are a certain distance apart. These two positive charges experience 3.6 N of repelling electrical force between them
So
here we use Columb law
Electric force = k * two charges * two charges)r^2
3.6 N = (8.99*10^9) * ( 5 * 10^-6) * (5*10^-6)r^2
r = 0.2499 m.
Hence, The distance that should be apart from these charges should be considered when the r = 0.2499 m.
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