PHYSICS QUESTION PAPER BTECH PTU

PHYSICS QUESTION PAPER PTU
PHY-101 B.Tech 1st & 2nd Semester,2063)
Maximum Marks : 60
Section - A
1(a) What do you understand by curl of a vector?
(b) Explain electromotive force.
(c) Why population inversion is essential for stimulated emission?
(d) An infinte charge sheet has a surface charge density (σ) of 1 x 10-7 coulomb/m2. How far apart are the equpotential surfaces whose potential differ by 5.0 volts ?
(e) What is numerical aperture?
(f) What are Einstein's postulates of relativity?
(g) What is Raman effect and its importance?
(h) Differentiate between Group and Phase velocities.
(i) Why good conductors are not good superconductors?
(j) If the potential difference applied across X-ray tube is 10kV and the current through it is 2 mA, calculate the velocity of electrons at which they strike the target.

Section-B
2. (a) Define electric potential and field at a point. Explain how we may calculate the electric field from the electric potential and vice versa.
(b) What is dielectric polarization and electric displacement?
3. (a) What is Biot-Savart Law? Find the intensity of magnetic field at a point on the axis of a circular ciol carrying current.
(b) Give Maxwell's equations.
4. (a) Explain the terms:
(i) Life time of an energy stste
(ii) Metastable states
(iii) Optical pumping and
(iv) Population inversion5. (a) Differentiate between step index and graded index fibre. Explain index material dispersion in pulse dispersion in optical fibres.
(b) Give some applications of optical fibres.

Section-C
6. (a) Discuss in detail the Michelson-Morley Experiment. (b) What is the total energy E of a 2.50 MeV elecrton? (mass of electron = 9.109 x 10-31 kg).7. (a) Differentiate between continuous and characteristics X-ray spectra. What is Brag's law? Give its derivation.
(b) What is Mosley's law and its importance?
8. (a) Write the Schrodinger wave equation for the particle in a box and solve it to obtain the Eigenvalues and Eigen functions. Explain briefly Uncertainty Principle.
9. What do you understand by Type I and Type II superconductors? Give the BCS theory of Superconductivity.