Advertisements
Advertisements
प्रश्न
A sample of 32P initially shows activity of one Curie. After 303 days, the activity falls to 1.5 × 104 dps. What is the half-life of 32P?
उत्तर
Given: 1 Ci = 3.7 × 1010 dps,
`("-dN"_0)/"dt" = 3.7 xx 10^10 "dps" and ("-dN"/"dt") = 1.5 xx 10^4` dps, t = 303 days
To find: t1/2
Formulae:
- `lambda = 2.303/"t" log_10 ("N"_0/"N")`
- `"t"_(1//2) = 0.693/lambda`
Calculation:
- `lambda = 2.303/"t" log_10 ("N"_0/"N")`
`lambda = 2.303/303 log_10 ((3.7 xx 10^10)/(1.5 xx 10^4)) ....[therefore (- "dN")/"dt" prop "N"]`
= 0.04859 d-1 - `"t"_(1//2) = 0.693/lambda = 0.693/0.0459`
= 14.27 d (by using log table)
Half-life of 32P is 14.27 days
APPEARS IN
संबंधित प्रश्न
Sample of carbon obtained from any living organism has a decay rate of 15.3 decays per gram per minute. A sample of carbon obtained from very old charcoal shows a disintegration rate of 12.3 disintegrations per gram per minute. Determine the age of the old sample given the decay constant of carbon to be 3.839 × 10−12per second.
Describe alpha, beta and gamma decays and write down the formulae for the energies generated in each of these decays.
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.
The half-life of 35S is 87.8 d. What percentage of 35S sample remains after 180 d?
0.5 g sample of 201Tl decays to 0.0788 g in 8 days. What is its half-life?
65% of 111In sample decays in 4.2 d. What is its half-life?
A 3/4 of the original amount of radioisotope decays in 60 minutes. What is its half-life?
The half-life of radon is 3.82 d. By what time would 99.9% of radon will be decayed?
In Hydrogen, the electron jumps from the fourth orbit to the second orbit. The wavenumber of the radiations emitted by an electron is ______
The decay constant λ of a certain radioactive material is 0.2166 per day. The average life τ of the radioactive material is ______
The half-life of a certain radioactive species is 6.93 × 105 seconds. What is the decay constant?
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 lifetime of radioactive material.
A radioactive substance decays to (1/10)th of its original value in 56 days. Calculate its decay constant.
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, ______
The activity of a radioactive sample ____________.
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:
The disintegration rate of a radio-active sample is 1010 per hour at 20 hours from the start. It reduces to 5 × 109 per hour after 30 hours. Calculate the decay constant.
Show that the number of nuclei of a radioactive material decreases exponentially with time.
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]
