Rani Durgavati Vishwavidyalaya 2009 B.Sc Physics GovtScience College, - Question Paper

Physics
Govt. Science College, Jabalpur

1. Two thin lenses of power + three D and – one D are in contact. What is the focal length of the combination ?
2. Define 'stopping potential' with reference to photo-electric effect.
3. Name the physical volume whose S I unit is newton/coulomb.
4. What should be the length of the dipole antenna for a carrier wave of 300 k Hz ?
5. What is the value of magnetic susceptibility of a diamagnetic material ?
6. Write 1 representative formula of nuclear fusion reaction.
7. Define the terms angle of dip' and 'vertical component of earth's magnetic field' at a place.
8. With the help of circuit diagram, define the use of zener diode as a voltage stabilizer.
9. You are provided n resistors, every of resistance R. These are 1st connected to get minimum possible resistance. In the 2nd case, these are again connected so as to get maximum possible resistance. Compare the ratio ranging from the minimum and maximum values of resistances so found.
10. State 2 main points of difference ranging from self-inductance and mutual inductance.
OR
A coil of inductance 100 m H and resistance 40 ? is connected to a 220 V, 50 Hz a c source. compute the impedance of the coil.
11. A radioactive nucleus A decays as follows :

If the mass number and atomic number of are 176 and 71 respectively, elaborate the mass numbers and atomic numbers of and A ?
12. Draw a labelled ray diagram to show the image formation in a refracting kind astronomical telescope when the final image is being formed at infinity.
13. The capacitance of a parallel plate air capacitor is six n F. What will be the capacitance if the distance ranging from the plates be decreased by rd and the space ranging from them is filled with a substance of dielectric constant four ?
14. Refractive index of carbon-di-sulphide is 1.62. obtain the value of critical angle in it.
15. Draw a diagram to show variation of thermoelectric emf produced in a thermocouple with temperature of hot junction. describe 'neutral temperature' and 'temperature of inversion'.
16. How will you use a metre bridge to measure an unknown resistance ? Draw the relevant circuit diagram.
17. For what purpose Davisson-Germer's experiment was performed ? obtain the ratio of de Broglie wavelengths associated with an ?-particle and a proton, if both particles have identical value of kinetic energy.
18. Draw a circuit diagram for a 2 input AND gate and discuss its working.
19. Distinguish ranging from analog and digital communication. Write any 2 modulation techniques employed for the digital data.
20. Draw a schematic diagram of a single optical fibre structure. define in brief, the mechanism of propagation of light signal through an optical fibre.
OR
Define the term 'critical frequency' in relation to sky wave propagation of electromagnetic waves.
On a particular day, the maximum frequency reflected from the ionosphere is 10 M Hz. On a different day, it was obtained to reduce to eight M Hz. compute the ratio of the maximum electron densities of the ionosphere on the 2 days.
21. Show mathematically that the avg. power supplied to an ideal capacitor by an a c source over a complete cycle is zero.
22. Draw a circuit diagram for use of a p-n-p transistor as an amplifier in common emitter configuration. The input resistance of a transistor is 500 ?. On changing the base current by 20 ? A, the collector current changed by one m A. If a load resistance of 10 k ? is used in the circuit, compute :
(i) the current gain,
(ii) voltage gain of the amplifier.
23. Write the order of frequency range and 1 use of every of the subsequent electromagnetic radiations :
(i) Ultra-violet rays,
(ii) Radio waves,
(iii) X-rays.
24. The primary coil of an ideal step up transformer has 100 turns and the transformation ratio is also 100. The input voltage and power are 220 V and 1100 W respectively. compute :
(i) number of turns in the secondary,
(ii) the current in the primary,
(iii) the current in the secondary.
25. Define the term binding energy of a nucleus. Draw a diagram to show the variation of binding energy per nucleon with mass number for various nuclei. State why light nuclei usually under go nuclear fusion.
26. (a) What are coherent sources of light ? State 2 conditions for 2 light sources to be coherent.
(b) Derive a mathematical expression for the width of interference fringes found in Young's double slit experiment.
OR
(a) Draw the geometrical shape of the wave fronts when (i) light diverges from a point source, and (ii) light emerges out of a convex lens when a point source is placed at its focus.
(b) State Huygen's principle. With the help of a suitable diagram, prove Snell's legal regulations of refraction using Huygen's principle.
27. Define dipole moment of an electric dipole. An electric dipole is held in a uniform electric field. Derive an expression for the torque acting on it.
An electric dipole of dipole moment is aligned parallel to a uniform electric field of . compute the work done in rotating it through 180.
OR
State Gauss' theorem. provide its mathematical expression. Derive an expression for the electric field strength at any point due to an infinite, plane, thin sheet of charge having charge density.
28. Derive a mathematical expression for the force per unit length experienced by every of the 2 long current carrying conductors placed parallel to every other in air. Hence describe 1 ampere of current. Also show that forces experienced by 2 conductors behave as action-reaction forces.
OR
Draw a neat labelled diagram of a cyclotron. State the underlying principle and discuss how a positively charged particle gets accelerated in this machine. Show mathematically that the cyclotron frequency does not depend upon the speed of the particle.

Earning:   Approval pending.