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Which of the following \alpha decay processes is expected to have a large Q value ? {}_{84}^{211}\text{Po}_0 \rightarrow {}_{82}^{207}\text{Po}_0 + \alpha {}_{84}^{212}\text{Po}_0 \rightarrow {}_{82}^{208}\text{Po}_0 + \alpha Which of these processes will have a longer lifetime ? Explain your answer briefly.
Explain why the decay process n \rightarrow p + e + \bar{\nu} is observed but the decay p \rightarrow n + e^+ + \nu is not observed.
What are mirror nuclei ? How does the charge independence of nuclear force emerge from this concept?
A star converts all its hydrogen to helium, achieving 100% helium composition. It then converts the helium to carbon via the reaction {}^{4}_{2}\text{He} + \text{He} \rightarrow {}^{12}_{6}\text{C} + 7.27\text{ MeV} The mass of the star is 5 \times 10^{32}\text{ kg} and it generates energy at the rate of 5 \times 10^{30}\text{ W}. How long will it take to convert all helium to carbon at this rate ?
Give some characteristic properties of strange particles which distinguish them from non-strange ones. Write the Gell-Mann-Nishijima relation. How is it used for the classification of elementary particles?
State the quantum numbers I_3, Y and S for the uds quarks and antiquarks. Which combination of these leads to the formation of (1) proton and (2) neutron ?
(i) Calculate the Q-value of the reaction ^9_4\text{Be} (^4_2\text{He}, n) ^{12}_6\text{C} Given \text{Mass } (^9\text{Be}) = 9.012183\text{ u} \text{Mass } (^4\text{He}) = 4.002603\text{ u} \text{Mass } (^{12}\text{C}) = 12.000\text{ u} Write down the nucleonic configuration of {}^{7}\text{Li}, {}^{12}\text{C}, {}^{17}\text{O} and {}^{27}\text{Al} in the ground state of the nuclear shell model and hence calculate the corresponding ground state angular momenta and parities. How do the observed ground state angular momenta and parities agree with those predicted on the basis of the shell model ?
Write down the Bethe-Weizsacker semi-empirical mass formula for a nucleus. Explain the significance of each term occurring in it. Discuss the stability of a nucleus against \beta-decay. What is the effect of pairing term on stability?
(i) Exlain the quark structure of hadrons. Identify the field of quark of electro-weak and electro-strong interactions. Also verify the conservation of strangeness in the following reactions : \hfill 10 \pi^- + p \rightarrow \Lambda^\circ + K^\circ K^+ \rightarrow \pi^+ + \pi^+ + \pi^- (ii) Drawing necessary diagrams, explain diamond structure and CsCl structures. \hfill 10
In the following reactions indicate with an explanation, whether they proceed by strong, electromagnetic or weak interaction or they are forbidden : \pi^+ \rightarrow \mu^+ + u_\mu p \rightarrow n + e^+ + u_e p + \pi^- \rightarrow K^+ + \Sigma^-
Name the various classifications of the gamma rays based on electric, magnetic and order. How does parity affect these radiations ?
Illustrate the Geiger-Nuttall law in a plot between the decay constant and energy of various nuclides for any radioactive series.
Describe briefly the different types of physical processes with which gamma rays are absorbed by matter as they are emitted.
Based on physical calculations, explain why deuteron is stable.
What is the role of neutrino in the weak interaction of radioactive nuclides ? Explain the experimental detection of neutrino.
(i) Discuss in detail the classification of elementary particles. \hfill 10 (ii) On the basis of band theory, explain the classification of solids by considering their electrical properties. \hfill 10
(i) Differentiate between K-capture and inverse \beta-decay. (ii) Explain what is internal conversion and how it differs from \beta-decay.
(i) Write the Weizacker mass formula and explain the significance of various terms. (ii) Determine the amount of _{84}^{210}\text{Po} necessary to provide a source of \alpha-particles of strength 5 \text{ mC}_i. The half-life of _{84}^{210}\text{Po} is 138 \text{ d}.
(i) What are the basic interactions in nature ? Give one example for each. Compare their relative strengths and ranges. (ii) What are the conservation laws for strong, electromagnetic and weak interactions ? (iii) Distinguish between particle and anti-particle. How was positron discovered ?
Describe how parity violation was experimentally detected in ^{60}\text{Co} \beta-decay. How was the observed asymmetry in the distribution of emitted electrons explained ?