Punjab Technical University 2007 Bachelor of Computer Science (B Level) PHYSICS, - Question Paper

PHYSICS
(B.Tech first & second Semester)
Time : three Hours Maximum Marks : 60
Instruction to candidates:
1) Section –A is compulsory.
2) Attempt any 4 ques. from section-B
3) Attempt any 2 ques. from section-C



part -A
Q1) (marks 10*2=20)

1(a) What do you understand by curl of a vector?
(b) discuss electromotive force.
(c) Why population inversion is essential for stimulated emission?
(d) An infinte charge sheet has a surface charge density (s) of one 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) elaborate Einstein's postulates of relativity?
(g) What is Raman effect and its importance?
(h) Differentiate ranging from 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 two mA, compute
the velocity of electrons at which they strike the target.

Section-B

2. (a) describe electric potential and field at a point. discuss how we may compute 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? obtain the intensity of magnetic field at a point on the axis of a circular ciol carrying current.
(b) provide Maxwell's equations.
4. (a) discuss the terms:
(i) Life time of an energy stste
(ii) Metastable states
(iii) Optical pumping and
(iv) Population inversion
5. (a) Differentiate ranging from step index and graded index fibre. discuss index material dispersion in pulse dispersion in
optical fibres.
(b) provide a few applications of optical fibres.

Section-C


6. (a) explain 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 ranging from continuous and characteristics X-ray spectra. What is Brag's law? provide its derivation.
(b) What is Mosley's legal regulations and its importance?
8. (a) Write the Schrodinger wave formula for the particle in a box and solve it to find the Eigenvalues and Eigen
functions.
discuss briefly Uncertainty Principle.
9. What do you understand by kind I and kind II superconductors? provide the BCS theory of Superconductivity.

Earning:   Approval pending.