Advertisements
Advertisements
प्रश्न
Write symbolically the process expressing the β+ decay of `""_11^22Na`. Also write the basic nuclear process underlying this decay.
Advertisements
उत्तर
The β+ decay for `""_11^22Na` is given below:
`""_11^22Na->_10^22Ne+beta^++v`
If the unstable nucleus has excess protons than required for stability, a proton converts itself into a neutron. In the process, a positron e+ (or a β+) and a neutrino ν are created and emitted from the nucleus.
p→n+β++ν
This process is called beta plus decay.
APPEARS IN
संबंधित प्रश्न
Obtain the amount of `""_27^60"Co"` necessary to provide a radioactive source of 8.0 mCi strength. The half-life of `""_27^60"Co"` is 5.3 years.
In a given sample, two radioisotopes, A and B, are initially present in the ration of 1 : 4. The half lives of A and B are respectively 100 years and 50 years. Find the time after which the amounts of A and B become equal.
A freshly prepared radioactive source of half-life 2 h emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which it would be possible to work safely with this source is
The decay constant of a radioactive sample is λ. The half-life and the average-life of the sample are respectively
A radioactive isotope is being produced at a constant rate dN/dt = R in an experiment. The isotope has a half-life t1/2. Show that after a time t >> t1/2 the number of active nuclei will become constant. Find the value of this constant.
Consider the situation of the previous problem. Suppose the production of the radioactive isotope starts at t = 0. Find the number of active nuclei at time t.
Disintegration rate of a sample is 1010 per hour at 20 hours from the start. It reduces to 6.3 x 109 per hour after 30 hours. Calculate its half-life and the initial number of radioactive atoms in the sample.
Obtain an expression for the decay law of radioactivity. Hence show that the activity A(t) =λNO e-λt.
What percentage of radioactive substance is left after five half-lives?
The activity R of an unknown radioactive nuclide is measured at hourly intervals. The results found are tabulated as follows:
| t (h) | 0 | 1 | 2 | 3 | 4 |
| R (MBq) | 100 | 35.36 | 12.51 | 4.42 | 1.56 |
- Plot the graph of R versus t and calculate the half-life from the graph.
- Plot the graph of ln `(R/R_0)` versus t and obtain the value of half-life from the graph.
