Search, filter, and study UPSC Civil Services & IFoS Physics past year questions with rigorous derivations, formulas, and step-by-step solutions.
An electric field of 100\ \mathrm{V/m} is applied to a sample of n-type semiconductor whose Hall coefficient is -0.0125\ \mathrm{m^3/coulomb}. Determine the current density in the sample assuming \mu_x = 0.36\ \mathrm{m^2\,V^{-1}\,s^{-1}}.
Calculate the energy released per gram of fuel for the nuclear reaction {}_1^2\text{H} + {}_1^2\text{H} \rightarrow {}_1^3\text{H} + {}_1^1\text{H}
It is possible to estimate the nuclear radius from the study of alpha decay? Explain how.
Discuss Yukawa’s theory of nuclear forces.
Explain why each of the following reactions is forbidden :
(i) p + p \rightarrow p + p + n
(ii) p + p \rightarrow p + \pi^+ + \gamma
(iii) \Xi^0 \rightarrow n + \pi^0
(iv) \Lambda \rightarrow p + \pi^0
(v) $ u_e + p \rightarrow n + e^+$
Explain in detail the classification of elementary particles.
Briefly explain the meson theory of nuclear force.
What are salient features of nuclear forces?
{}_{14}^{27}\text{Si} and {}_{13}^{27}\text{Al} are mirror nuclei. Their ground states are identical except the charge. If their mass difference is 6\text{ MeV}, estimate their radius neglecting the proton-neutron mass difference.
Explain how the nuclear spin I depends on the mass number A and atomic number Z of atoms.
How does liquid drop model explain fission?
What are the major components of a fission reactor ? With a schematic diagram explain its working.
Explain why stable light nuclei have equal number of protons and neutrons whereas heavy nuclei have excess of neutron.
What are the limitations of shell model?
What are the magic numbers in nuclei? List the experimental evidences indicating their existence.
How does the semi-empirical mass formula explain the stability of a nucleus against beta decay ?
How are elementary particles classified on the basis of their participation in fundamental interaction?
An atom in an excited state of 4\cdot 7\text{ eV} emits a photon and ends up in the ground state. The lifetime of the excited state is 10^{-13}\text{ s}. Calculate the energy uncertainty and obtain the spectral line width in wavelength of photon.
What are the characteristics of a Raman spectrum ? How do you study Raman spectra in the laboratory ? Give two applications of Raman effect.
Discuss the vibrational spectra of a diatomic molecule treating it as an anharmonic oscillator.