Exam Details
| Subject | ||
| Paper | ||
| Exam / Course | mains | |
| Department | ||
| Organization | Haryana Public Service Commission | |
| Position | physics | |
| Exam Date | 2011 | |
| City, State | haryana, |
Question Paper
PHYSICS (Code
Time: 3 Hours
Maximum Marks: 150
NOTE: Attempt FIVE questions in all. All questions carry equal marks, i.e., 30. Q.No.l is compulsory.
Answer any two questions from Part-I and any two questions from Part-II. The parts of the same question
must be answered together and must not be interposed between answers to other questions.
1. Write short notes on any FOUR of the followings: (4x7.5)
Coriolis force.
Wein's law.
Ruby laser.
. Ferromagnetic materials.
Compton effect.
Intrinsic extrinsic semiconductors.
PART-I
2. What is a central force? Give an example. How will you find out if a given force is central or not?
Two particles ofthe same mass are moving along a straight path with velocity VI and Vz respectively. Show that the momentum ofthe system in the centre ofmass system is zero.
Explain briefly the objective of Michelson-Morley experiment.
3. State and explain Stefan's law of black body radiation.
The surface ofa furnace is at a temperature of 1427 centigrade. Ifthe Stefan's constant is 5.7xIO-8 W/mZ/K4 and assuming furnace surface to be a black body, how much heat is radiated by 2 mZ of The surface in 1 hour?
Assuming Maxwell-Boltzmann distribution of velocities to hold, what is the relation between the rootmean-square and the average speed of molecules of a gas? What is the relation between the average speed and the most probable speed?
4. Show that superposition oftwo mutually perpendicular SHMs ofequal amplitude and phase differences of 90° is a circular motion.
Obtain expression for the resolving power of a grating.
A particle executes SHM with a frequency of2Hz and amplitude 0.05m. Calculate the maximum and the minimum magnitudes ofthe acceleration.
PART-II
5. A conducting hollow sphere of radius R1 meter is concentrically surrounded by another conducting hollow sphere of radius Rz meter. The charges on the two spheres are ql and qz coulomb respectively. What is the electrostatic potential at a distances x x Rz) from their common centre?
What is power factor ofan alternating circuit? How much is its value for an LCR series circuit at resonance?
IIITN-EB-12
A current carrying circular coil is of radius R. Calculate the ratio ofthe magnetic induction at the centre of the coil and at a point a distance R from the centre and on the axis ofthe coil.
6. (a)Photons of energy 3.0eV fall on a photoelectron emitter of work function 2.5eV. The emitted electrons are subjected to a transverse uniforms magnetic field of induction B. Calculate the minimum value ofB so that all emitted electrons move in circles ofradii less than 0.1 m.
(b)Define decay constant, activity and mean life with reference to radioactive decay. Also define a Curie.
7. Explain briefly the mechanism of development ofbuilt-in potential barrier during the formation of a p-njunction.
Draw the common-emitter output characteristics ofa transistor and identify its different regions of operation. In which regions it works as an amplifier? Explain.
Write the truth-tables for AND OR gates.
II/TN-EB-12 2
Time: 3 Hours
Maximum Marks: 150
NOTE: Attempt FIVE questions in all. All questions carry equal marks, i.e., 30. Q.No.l is compulsory.
Answer any two questions from Part-I and any two questions from Part-II. The parts of the same question
must be answered together and must not be interposed between answers to other questions.
1. Write short notes on any FOUR of the followings: (4x7.5)
Coriolis force.
Wein's law.
Ruby laser.
. Ferromagnetic materials.
Compton effect.
Intrinsic extrinsic semiconductors.
PART-I
2. What is a central force? Give an example. How will you find out if a given force is central or not?
Two particles ofthe same mass are moving along a straight path with velocity VI and Vz respectively. Show that the momentum ofthe system in the centre ofmass system is zero.
Explain briefly the objective of Michelson-Morley experiment.
3. State and explain Stefan's law of black body radiation.
The surface ofa furnace is at a temperature of 1427 centigrade. Ifthe Stefan's constant is 5.7xIO-8 W/mZ/K4 and assuming furnace surface to be a black body, how much heat is radiated by 2 mZ of The surface in 1 hour?
Assuming Maxwell-Boltzmann distribution of velocities to hold, what is the relation between the rootmean-square and the average speed of molecules of a gas? What is the relation between the average speed and the most probable speed?
4. Show that superposition oftwo mutually perpendicular SHMs ofequal amplitude and phase differences of 90° is a circular motion.
Obtain expression for the resolving power of a grating.
A particle executes SHM with a frequency of2Hz and amplitude 0.05m. Calculate the maximum and the minimum magnitudes ofthe acceleration.
PART-II
5. A conducting hollow sphere of radius R1 meter is concentrically surrounded by another conducting hollow sphere of radius Rz meter. The charges on the two spheres are ql and qz coulomb respectively. What is the electrostatic potential at a distances x x Rz) from their common centre?
What is power factor ofan alternating circuit? How much is its value for an LCR series circuit at resonance?
IIITN-EB-12
A current carrying circular coil is of radius R. Calculate the ratio ofthe magnetic induction at the centre of the coil and at a point a distance R from the centre and on the axis ofthe coil.
6. (a)Photons of energy 3.0eV fall on a photoelectron emitter of work function 2.5eV. The emitted electrons are subjected to a transverse uniforms magnetic field of induction B. Calculate the minimum value ofB so that all emitted electrons move in circles ofradii less than 0.1 m.
(b)Define decay constant, activity and mean life with reference to radioactive decay. Also define a Curie.
7. Explain briefly the mechanism of development ofbuilt-in potential barrier during the formation of a p-njunction.
Draw the common-emitter output characteristics ofa transistor and identify its different regions of operation. In which regions it works as an amplifier? Explain.
Write the truth-tables for AND OR gates.
II/TN-EB-12 2