<u>Answer:</u> The mass of sample A after given time is 99.05 g.
<u>Explanation:</u>
All the radioactive reactions follows first order kinetics.
The equation used to calculate half life for first order kinetics:
We are given:
Putting values in above equation, we get:
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = 84.2 s
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = 250 g
[A] = amount left after decay process = ?
Putting values in above equation, we get:
![0.011s^{-1}=\frac{2.303}{84.2s}\log\frac{250}{[A]}](https://tex.z-dn.net/?f=0.011s%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7B84.2s%7D%5Clog%5Cfrac%7B250%7D%7B%5BA%5D%7D)
![[A]=99.05g](https://tex.z-dn.net/?f=%5BA%5D%3D99.05g)
Hence, the mass of sample A after given time is 99.05 g.
The wavelength is obtained as 122 nm. Option A
<h3>What is the wavelength?</h3>
We know that from the Bohr model of the atom, an electron can move from a higher energy level to a lower energy level or from a lower energy level to a higher energy level. This is the idea of energy quantization as put forward by Neill Bohr.
The wavelength can be obtained by the use of the formula;
1/λ = RH(1/n^2initial - 1/n^2 final)
λ = wavelength of the emitted light
RH = Rydberg's constant
n intial = initial energy level
nfinal = final energy level
Thus;
1/λ = 1.09 * 10^7(1/1^2 - 1/2^2)
1/λ = 1.09 * 10^7( 1 - 0.25)
λ = 122 nm
Learn more about the wavelength:brainly.com/question/13533093
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Answer:
im sorry that i cant help have you try looking it up?
Explanation:
Answer:
I think its B im not sure lol but I would wait for someone that actually would know for sure
