Advertisements
Advertisements
Question
0.5 g sample of 201Tl decays to 0.0788 g in 8 days. What is its half-life?
Advertisements
Solution
Given: N0 = 0.5 g, N = 0.0788 g, t = 8 days
To find: t1/2
Formulae:
- `lambda = 2.303/"t" log_10 ("N"_0/"N")`
- t1/2 = `0.693/lambda`
Calculation:
1. `lambda = 2.303/"t" log_10 ("N"_0/"N")`
`= 2.303/8 log_10 (0.5/0.0788)`
`= 2.303/8 log_10 (6.3452)`
`= 2.303/8 xx 0.8024`
λ = 0.231 d-1
2. `"t"_(1//2) = 0.693/lambda`
`"t"_(1//2) = 0.693/0.231`
`"t"_(1//2)` = 3d
The half-life of 201Tl is 3d.
APPEARS IN
RELATED QUESTIONS
What is gamma decay?
Complete the following equation describing nuclear decay.
\[\ce{_88^226Ra->_2^4\alpha {+}}\] ______.
Complete the following equation describing nuclear decay.
\[\ce{_8^19O->e^- { +}}\] _____
Complete the following equation describing nuclear decay.
\[\ce{_90^228Th->\alpha { +}}\] _____
Complete the following equation describing nuclear decay.
\[\ce{_7^12N -> _6^12C {+}}\] ______
Write relation between decay constant of a radioelement and its half-life.
Decay constant of 197Hg is 0.017 h-1. What is its half-life?
The half-life of 35S is 87.8 d. What percentage of 35S sample remains after 180 d?
The half-life of 67Ga is 78 h. How long will it take to decay 12% of the sample of Ga?
65% of 111In sample decays in 4.2 d. What is its half-life?
A sample of old wood shows 7.0 dps/g. If the fresh sample of tree shows 16.0 dps/g, how old is the given sample of wood? (Half-life of 14C is 5730 y)
Show that for radioactive decay N(t) = `"N"_"O" "e"^{-λ"t"}`, where symbols have their usual meaning.
Obtain an expression for the half-lifetime of radioactive material. Hence state the relation between an average life and half life time of radioactive material.
A radioactive substance decays to (1/10)th of its original value in 56 days. Calculate its decay constant.
Most excited states of an atom have life times of about ____________.
What is alpha decay?
What is beta decay?
A radioactive element has rate of disintegration 10,000 disintegrations per minute at a particular instant. After four minutes it become 2500 disintegrations per minute. The decay constant per minute is ______.
A radioactive sample S1 having the activity A1 has twice the number of nuclei as another sample S2 of activity A2 If A2 = 2A1 then the ratio of half-life of S1 to the half-life of S2 is ______.
The graph obtained by plotting loge (A) [A is the activity of a radioactive sample] against t (time) out of the following is:
If the number of nuclei of a radioactive substance becomes `1/e` times the initial number in 10 days, what is the decay constant of the substance?
The half-life of \[\ce{^238_92U}\] undergoing ∝- -decay is 4.5 × 109 years. What is the activity of 1g sample of \[\ce{^238_92U}\]?
Define half-life period.
In one mean lifetime of a radioactive element the fraction of the nuclei that has disintegrated is ______. [e is the base of natural logarithm]
