Problem 120
Which of the following pairs are isodiapheric pairs? (a) \({ }_{29} \mathrm{Cu}^{65}\) and \({ }_{24} \mathrm{Cr}^{55}\) (b) \({ }_{29} \mathrm{Cu}^{65}\) and \({ }_{24} \mathrm{Cr}^{52}\) (c) \({ }_{92} \mathrm{U}^{235}\) and \({ }_{90}^{20} \mathrm{Th}^{231}\) (d) \({ }_{92} \mathrm{U}^{238}\) and \({ }_{90} \mathrm{Th}^{231}\)
Problem 121
In the decay process $$ \mathrm{P} \stackrel{-\alpha}{\longrightarrow} \mathrm{Q} \stackrel{-\beta}{\longrightarrow} \mathrm{R} \stackrel{-\beta}{\longrightarrow} \mathrm{S} $$ (a) \(\mathrm{P}\) and \(\mathrm{R}\) are isotones (b) \(\mathrm{Q}, \mathrm{R}\) and \(\mathrm{S}\) are isobars (c) \(\mathrm{P}\) and \(\mathrm{S}\) are isotopes (d) \(\mathrm{P}\) and \(\mathrm{Q}\) are isobars
Problem 122
Which is/are correct about the properties of rays? (a) Effect on photographic film : \(\alpha>\beta>\lambda\). (b) Velocity : \(\alpha<\beta<\lambda\). (c) Penetration power : \(\alpha<\beta<\lambda\). (d) Ionising power : \(\alpha>\beta>\lambda\).
Problem 123
Which relation is/are correct? (a) \(1 \mathrm{Ci}=3.7 \times 10^{10} \mathrm{~Bq}\) (b) \(1 \mathrm{Ci}=2.8 \mathrm{v} 10^{4} \mathrm{Rd}\) (c) \(1 \mathrm{~Bq}=1\) dps. (d) \(1 \mathrm{~Bq}=10^{6} \mathrm{Rd}\)
Problem 124
Which of the following statements is/are incorrect, when the nuclide, \({ }_{19} \mathrm{~K}^{40}\), is subject to \(\mathrm{K}\)-electron capture? (a) \({ }^{40} \mathrm{Ar}\) is produced with emission of \(\beta\)-particle. (b) \({ }^{40} \mathrm{Ar}\) is produced with emission of \(\alpha\)-particles. (c) \({ }^{40} \mathrm{Ar}\) is produced without emission of radiation (d) \({ }^{40} \mathrm{Ar}\) is produced with emission of X-radiation.
Problem 125
An unstable nucleus is characterized by (i) \(\mathrm{n} / \mathrm{p}>1\) (ii) low binding energy (iii) high temperature and pressure (iv) high packing fraction (a) (i), (ii) (b) (i), (ii), (iv) (c) (i), (ii), (iii) (d) (i), (ii), (iii), (iv)
Problem 127
How much time is required for a \(5.75-\mathrm{mg}\) sample of \({ }^{51} \mathrm{Cr}\) to decay to \(1.50 \mathrm{mg}\) if it has a half-life of \(27.8\) days? (a) \(5.39\) days (b) \(2.69\) days (c) \(53.9\) days (d) \(5.49\) days
Problem 128
Potassium \(-40\) decays to argon \(-40\) with a half life of \(1.27 \times 10^{9} \mathrm{yr}\). What is the age of a rock in which the mass ratio of \({ }^{40} \mathrm{Ar}\) to \({ }^{40} \mathrm{~K}\) is \(3.6\) ? (a) \(2.8 \times 10^{10} \mathrm{yr}\) (b) \(1.4 \times 10^{9} \mathrm{yr}\) (c) \(1.4 \times 10^{10} \mathrm{yr}\) (d) \(2.8 \times 10^{9} \mathrm{yr}\)
Problem 129
Which of the following option is correct? (a) In living organisms, circulation of \({ }^{14} \mathrm{C}\) from atmosphere is high so the carbon content is constant in organism. (b) carbon dating can be used to find out the age of earth crust and rocks (c) radioactive absorption due to cosmic radiation is equal to the rate of radioactive decay, hence the carbon content remains constant in living organism (d) carbon dating can not be used to determine concentration of \({ }^{14} \mathrm{C}\) in dead beings.
Problem 133
Match the following Column-I (Reactions) (a) \({ }_{4} \mathrm{Be}^{9}+{ }_{2} \mathrm{He}^{4} \rightarrow{ }_{6} \mathrm{C}^{12}+\ldots \ldots\) (b) \({ }_{6} \mathrm{C}^{12}+\ldots \ldots \rightarrow{ }_{5} \mathrm{~B}^{10}+{ }_{2} \mathrm{He}^{4}\) (c) \({ }_{7} \mathrm{~N}^{14}+\ldots \ldots \rightarrow{ }_{8} \mathrm{O}^{17}+{ }_{1} \mathrm{H}^{1}\) (d) \({ }_{20} \mathrm{Ca}^{40}+\ldots \ldots \rightarrow{ }_{19} \mathrm{~K}^{37}+{ }_{2} \mathrm{He}^{4}\) Column-II (Particles) (p) \({ }_{2} \mathrm{He}^{4}\) (q) \({ }_{0} \mathrm{n}^{1}\) (r) \({ }_{1} \mathrm{D}^{2}\) (s) \({ }_{1} \mathrm{H}^{1}\)
