CSS 2017 Physics Combined Papers Past Paper

Paper details

Examination

CSS

Year

2017

Subject

Physics

Paper

Combined Papers

Subject type

Optional

Mode

Subjective

Questions recorded from this paper

These 12 question wordings are transcribed from CSS Vista’s structured Physics past-paper record for CSS 2017.

1. Q7 · Mechanics(a) What do you understand by classical statistical mechanics and quantum (6) statistical mechanics? (b) Differentiate between Fermi-Dirac, Bose-Einstein and Maxwell-Boltzman’s (6) statistics. (c) What is equipartition of energy? Explain. (5) (d) A 0.5m3 vessal is filled with air at atmospheric pressure. The air is churned (3) (20) by a paddel wheel attached to a shaft 0.1m in diameter, rotating at a speed of 1800 rpm. A force of 5.0N acts on the rim of the shaft. What would be the pressure in the vessel after 10 sec of operation
2. Q2 · divergence(a) What is the cross product of two vectors? Why the cross product is called (5) pseudo vector? (b) What is divergence of vector field? What is its physical significance? (5) (c) What is line integral? Under what condition it is used to calculate the work (5) done. (d) Consider three vectors: (5) (20)    A  3iˆ  3 ˆj  2kˆ B  2iˆ  4 ˆj  2kˆ and C  2iˆ  3 ˆj  1kˆ       (i) Find A  ( BXC ) (ii) Find AX ( B XC )
3. Q5 · divergence(a) What is unique about light from a laser source, and why should you never (5) look directly into a laser beam? Explain briefly. (b) What is plasma? What do you mean by plasma frequency? Briefly discuss. (5) (c) How the blue laser is useful in storing large amount of data on a CD as (5) compared to red laser? (d) For the He-Ne laser at 2m and 4m distances from the laser, the output beam (5) (20) spot diameters are 2 mm and 3 mm. Calculate the angle of divergence.
4. Q4 · Phase and Group velocity(a) What do you mean by phase and group velocity? Derive a relation between a (7) group and phase velocity. (b) What is superposition of waves? Show that the standing waves are produced (7) by the superposition of two waves of equal amplitudes moving in opposite direction. (c) A medium is disturbed by an oscillation described by, (3) Y = 3.0cm sin(πx/10cm) cos (50πt) Determine the amplitude, frequency, wavelength, speed and direction of the component waves whose superposition produces this result. (d) If light of λ = 660nm has wave train 20λ, what is its coherence length and (3) (20) coherence time?
5. Q6 · temperature(a) What is viscosity? Discuss effect of temperature on the viscosity of liquids (6) and gases. (b) Differentiate between streamline and turbulent flow and establish equation of (4) continuity. (c) Explain why the level of mercury is down in capillary when placed in (6) container of mercury, while it is up in the capillary in case of water? (d) A garden hose has an inside diameter of 2 cm and water flows through it is at (4) (20) 3 m/s. (i) What nozzle diameter is required for the water to emerge at 10 m/s? (ii) At what rate does the water leave the nozzle?
6. Q8 · kinetic theory of gasesWrite notes on any FOUR of the following: (5 each) (20) (a) Polarization of light and its application in determining specific rotation of a liquid. (b) Wave equation on a string. (c) Normal and anomalous dispersion of light. (d) Kinetic theory of gases. (e) Scalar Triple product. Roll Number
7. Q2 · Electric potential(a) What is dipole moment? Obtain the expression for the potential and field (10) due to an electric dipole. (b) Calculate the potential at a point on the axis of circular plastic disk of (8) radius R, one surface of which carries a uniform charge density σ. (c) Why do we use unit “electron volts”? (2) (20)
8. Q3 · Ampere’s law(a) State and explain the Biot Savart law. (4) (b) State and prove Ampere’s law. Apply it to calculate the magnetic field (10) due to a solenoid. (c) A long straight wire carries a current of 20 Amperes. An electron at 2.0 (6) (20) cm from the wire is travelling at a speed of 107 m/sec. What force acts on the electron if its motion is directed (1) towards the wire, (2) parallel to the wire and (3) at right angles to the direction given in (1) and (2).
9. Q4 · Maxwell's equations in integral and differential form(a) Write the Maxwell’s equations and explain the significance of each (6) equation. (b) Deduce the Maxwell equations for free space and also prove that (12) electromagnetic waves are transverse. (c) What is index of refraction? (2) (20)
10. Q8 · time dependent and independent Schrodinger equationWriter short notes on any TWO of the following: (10 each) (20) (a) Schrodinger equation (b) Linear accelerator (c) Cyclotron
11. Q5 · Bohr’s theory and quantum numbers including electron spin(a) Describe the Stern Gerlach experiment that provided experimental (10) evidence of the space quantization of atomic magnetic moments. (b) What is the physical significance of the three quantum numbers n, 1, and (6) m in the labelling of the hydrogenic wave functions? (c) What do you understand by strange particles? (4) (20)
12. Q7 · n and p type semiconductors(a) Differentiate the Metals, Semiconductors and Insulators on the basis of (6) Energy Band Theory. (b) What is a rectifier? How we can use diode as a rectifier? Explain half- (14) (20) wave rectification in detail with diagrams.

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