Modern Physics

1) A moving hydrogen atomin ground state, causing radiation of several wavelengths, the longest of which is 1880 nm. From the consideration of the loss in KE in collision, what is the velocity above which the atom has to move initially??

2)A radioactive sample simultaneosly decays via two alternative processes, the mean life of one being equal to the half-life of the other (each equal to T). The time at which thepopulation of the undecayed nuclei equals sum of daughter nuclei is

(a) \left(\frac{1}{1+ln2} \right)T

(b) \left(1+ln2 \right)T

(c) \left(\frac{ln2}{1+ln2} \right)T

(d) \left(\frac{1+ln2}{ln2} \right)T

3)

16 Answers

11
Anirudh Narayanan ·

3) If the propbabiity that a radioactive nuclide is undecayed after two years is p, then it's disintegration constant is (in year-1)

(a) ln\left(\frac{1}{\sqrt{p}} \right)

(b) ln\left(\frac{1}{p} \right)

(c) ln\left(\sqrt{p} \right)

(d) ln\left(p \right)

1
Pavithra Ramamoorthy ·

in first q first line make it clear.....

i ve to tk dat a hydrogen atom is movin to ground state????????

21
tapanmast Vora ·

3A

11
Anirudh Narayanan ·

OK reposting first question:

1) A moving hydrogen atom in the ground state collides with a stationary hydrogen atom in the ground state, causing radiation of several wavelengths, the longest os which is 1880 nm. From the consideration of the loss in KE in collision, what is the velocity above which the atom has to move initially??

1
Pavithra Ramamoorthy ·

srry ani got it..

u ve not left space between atom and in. dats d prob....

now i got it.......

11
Anirudh Narayanan ·

tapan, if u can explain ur answer, it wud be easier for everyone else

Also, i don't have the solutions.....so pls explain ur answer

11
Anirudh Narayanan ·

?????

11
Anirudh Narayanan ·

Someone please solve this.... [2]

62
Lokesh Verma ·

3) If the propbabiity that a radioactive nuclide is undecayed after two years is p, then it's disintegration constant is (in year-1)

let λ is the constant

then no of those decaying in 2 years

N = N0e-2λ

N / N0 = e-2λ

probab of surviving 2 years = p = N/N0 = e-2λ

so -1/2 ln(P) = λ

λ = ln(1/√P)

11
Anirudh Narayanan ·

What about questions 1 and 2??

Someone pls do them!!!

1
vector ·

i q1which type of loses we ve to consider cud u specify

1
Pavithra Ramamoorthy ·

he has given it as loss of kinetic energy... ( due to collision)

11
Anirudh Narayanan ·

sorry, sister.....i've posted the complete question in post #5

1
vector ·

kkkk.. i din see that#5 so i was asking

62
Lokesh Verma ·

2)A radioactive sample simultaneosly decays via two alternative processes, the mean life of one being equal to the half-life of the other (each equal to T). The time at which thepopulation of the undecayed nuclei equals sum of daughter nuclei is

dA/dt = -k1 - k2

A=A0 ek1+k2

now we have that

.693/k1 = 1/2 x 0.693/k2
2 k2 = k1

now can you solve it..

1
Pavithra Ramamoorthy ·

1) is it 205.5 m/s?????

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