B different skills as every subject varies from each other
Answer:
2578.99 years
Explanation:
Given that:
100 g of the wood is emitting 1120 β-particles per minute
Also,
1 g of the wood is emitting 11.20 β-particles per minute
Given, Decay rate = 15.3 % per minute per gram
So,
Concentration left can be calculated as:-
C left = ![[A_t]=\frac{11.20\ per\ minute}{15.3\ per\ minute\ per\ gram}\times [A_0]= 0.7320[A_0]](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5Cfrac%7B11.20%5C%20per%5C%20minute%7D%7B15.3%5C%20per%5C%20minute%5C%20per%5C%20gram%7D%5Ctimes%20%5BA_0%5D%3D%200.7320%5BA_0%5D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
Also, Half life of carbon-14 = 5730 years
Where, k is rate constant
So,
The rate constant, k = 0.000120968 year⁻¹
Time =?
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
So,
![\frac {[A_t]}{[A_0]}=e^{-0.000120968\times t}](https://tex.z-dn.net/?f=%5Cfrac%20%7B%5BA_t%5D%7D%7B%5BA_0%5D%7D%3De%5E%7B-0.000120968%5Ctimes%20t%7D)
![\frac {0.7320[A_0]}{[A_0]}=e^{-0.000120968\times t}](https://tex.z-dn.net/?f=%5Cfrac%20%7B0.7320%5BA_0%5D%7D%7B%5BA_0%5D%7D%3De%5E%7B-0.000120968%5Ctimes%20t%7D)
<u>t = 2578.99 years</u>
Answer: Root nodules are associations between bacteria and plant roots responsible for nitrogen fixation.
Explanation:
- As nitrogen present in atmosphere cannot be used by plants directly.
- Nitrogen present in atmosphere is converted into nitrogen compounds by bacteria which is present in root nodules of a plant.
- These compounds of nitrogen are then used by plants for various functions.
Answer:
They all have the same number of protons but different numbers of neutrons.
Explanation:
These are called isotopes. Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.
The atomic number is the number of protons in an atom. For a neutral atom, it is the same as the number of electrons.
The mass number is the number of protons and neutrons in an atom.
silicon-28 (28Si)
silicon-29 (29Si)
silicon-30 (30Si)
All of these isotopes have an atomic number of 16
Now let us chech for the neutrons:
Number of neutrons = mass number - atomic number:
for silicon-28 (28Si) : 28-16 = 12 neutrons
silicon-29 (29Si)
: 29-16 = 13 neutrons
silicon-30 (30Si): 20-16 = 14 neutrons.
