Physics
Full Marks: 60
Pass Marks: 24
Time: 3 hours
Attempt any two questions: (2 × 10=20)
Explain the meaning of “fabrication of integrated circuits”. Describe following processes involved in the fabrication of integrated circuits: epitaxial growth, oxidation, oxide removal and pattern defination, doping and interconnection of components. [10]
Explain the effect of external magnetic field on current carrying loops. Describe torque on a current-carrying rectangualar loop of wire on a pivot rod when placed in a magnetic field. Give alternative way of increasing the torque on the coil. [10]
What do you mean by the wavefunction? Discuss its physical significance. Set up time-independent and time-dependent Schrodinger wave equation. What are the implications of this equation? Discuss.
Attempt any eight questions: (8 × 5=40)
Derive expression for electrical conductivity of semiconductor in terms of impurity ionization energy. [5]
Describe behaviour of mobile negative charges in the Hall effect experiment. [5]
Set up differential equation for an oscillation of a spring using Hooke’s and Newton’s second law. [5]
What are (a) the energy, (b) the momentum, and (c) the wavelength of a photon that is emitted when a hydrogen atom undergoes a transition from the n = 4 to the n = 2? [5]
An oscillating block of mass 250g takes 0.15 sec to move between the endpoints of the motion, which are 40cm apart. Find (a) frequency and (b) amplitude of the motion, and (C) force constant of the spring. [5]
A potential difference of 100 V is established between the two plates one being the high potential plate (say A). A photon of charge q = 1.6 x 10-19 C is released from plate B, the another plate. What will be the velocity of the proton when it reaches plate A? The mass of the proton is 1.67 x 10-27 kg. [5]
An α-particle is emotted from a radioactive nuclei with an energy of 6.8 MeV. Calculate its wavelength and compare it with the size of the emitting nucleus that has a radius of 8 x 10-15 m. [5]
(a) Calculate the Fermi energy aluminium that have density 2.3 g/cm3 and molecular weight 26.98 g/mole. (b) If the experimental value of Fermi energy(Ef) is 11.8 eV, what is the effective mass of electron in aluminium? Aluminium is trivalent. [5]
The output of a digital circuit (y) is given by this expression: