Advertisements
Advertisements
प्रश्न
The half-life of 35S is 87.8 d. What percentage of 35S sample remains after 180 d?
Advertisements
उत्तर
Given: t1/2 = 87.8 d, N0 = 100, t = 180 d
To find: % of 35S that remains after 180 days
Formulae:
- `lambda = 0.693/("t"_(1//2))`
- `lambda = 2.303/"t" log_10 ("N"_0/"N")`
Calculation:
- `lambda = 0.693/("t"_(1//2)) = 0.693/(87.8 "d") = 7.893 xx 10^-3 "d"^-1`
- Now, `lambda = 2.303/"t" log_10 ("N"_0/"N")`
`log_10 ("N"_0/"N") = (lambda"t")/2.303`
`= (7.893 xx 10^-3 xx 180)/2.303`
= 0.617
Taking antilog on both sides we get,
`"N"_0/"N" = 4.140`
N = `100/4.140`
= 24.155 ≈ 24.2%
Percentage of 35S that remains after 180 d is 24.2%.
APPEARS IN
संबंधित प्रश्न
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.
\[\ce{_7^12N -> _6^12C {+}}\] ______
Choose the correct option.
\[\ce{^60_27CO}\] decays with a half-life of 5.27 years to produce \[\ce{^60_28Ni}\]. What is the decay constant for such radioactive disintegration?
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?
A 3/4 of the original amount of radioisotope decays in 60 minutes. 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)
In Hydrogen, the electron jumps from the fourth orbit to the second orbit. The wavenumber of the radiations emitted by an electron is ______
The half-life of a certain radioactive nucleus is 3.2 days. Calculate (i) decay constant (ii) average life of radioactive nucleus.
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.
The rate of radioactive disintegration at an instant for a radioactive sample of half-life 2.2 x 109 s is 1010 s-1. The number of radioactive atoms in that sample at that instant is, ______
Most excited states of an atom have life times of about ____________.
The activity of a radioactive sample ____________.
A radioactive substance has half life of 3 hours. 75 % of the substance would decay in ____________.
What is alpha decay?
What is beta decay?
The radioactivity of a sample is R1 at a time T1 and R2 at a time T2. If the half-life of the specimen is T, the number of atoms that have disintegrated in the time (T1 - T2) is proportional to ______.
The half-life of a radioactive substance is 10 days. The time taken for the `(7/8)^"th"` of the sample of disintegrates is ______.
The graph obtained by plotting loge (A) [A is the activity of a radioactive sample] against t (time) out of the following is:
Show that the number of nuclei of a radioactive material decreases exponentially with time.
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]
