physics -i paper

8/7/2019 Physics -I Paper

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DISTRICT RESOURCE CENTREMAHBUBNAGAR

PRE-FINAL EXAMINATIONS - JAN / FEB -2011

PHYSICS - Paper ITime: 3 hrs Max. Marks 100

SECTION A

I. Answer all questions. 4 x 15 = 601. (a) Define the divergence of a vector field.

State and prove Gauss divergence theoremOr

(b) Obtain an expression for the motion of a rocket under constant gravitational field.

2. (a) What is precession? Derive an expression for precessional velocity of symmetric top?Or(b) Explain Michelson Morley experiment.

3. (a) Explain the torsional pendulum and obtain an expression for rigidity modulus of thematerial of a given wire.

Or(b) Analyse the square wave using Fouriers theorem.

4. (a) What are the transverse waves? Obtain the equation for the velocity of a transversewave in a stretched string.

Or(b) What are ultrasonic waves? Explain the production of ultrasonics by

magnetostriction method.

SECTION B

II. Answer any four questions. 4 x 5 = 20

5. Explain the scalar and vector fields.

6. Write Keplers Law.

7. Prove the conservative force is equal to the negative gradient of potential energy.

8. Obtain an expression for the equation of continuity.9. State two postulates of special theory of relativity and write the Galilean

transformation equations.

10. What are shock waves? What is Mach number?

11. Define the impact parameter and scattering cross section.12. What is relaxation time? And write the equation for mechanical energy of damped

harmonic Oscillator?

(P.T.O.)


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SECTION C

III. Solve any four problems 4 x 5 = 20

13. If ( x , y, z) = 3 x 2 + yz 3 + z then find the value of

at (2, 1, -2)

14. the youngs modulus for steel is 2 x 10 11

2mN

and its rigidity modulus is 8 x 10 10 2mN

.

Find the poissons ratio.

15. Find the fundamental frequency of a string of 50cm length and mass of 5gram. When400N tension is applied.

16. The K.E of metal disc rotating at a constant speed of 5 revolutions per second is

100 J. Find the angular momentum of the disc

17. If the earth be one-half of its present distance from the sun what will be number of days in a year?

18. In the laboratory the life time of a particle moving at a speed of 2.8 x 10 10 Scm

is found to

be 2.5 x 10 -7S, find the proper life time of the particle.

19. A peiogo electric crystal has a thickness of 0.002m. If the velocity of wave in crystal is5750 m/s, calculate the fundamental frequency of crystal.

20. The Q-factor of a sonometer wire is 2.2 x 10 3. On plucking it executes 210 vibrations

per second. Calculate time in which the amplitude decreases to 2e

1of the initial value.

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DISTRICT RESOURCE CENTREMAHBUBNAGAR

PRE-FINAL EXAMINATIONS - JAN / FEB -2011PHYSICS - Paper I

Time: 3 hrs Max. Marks 100

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physics -i paper

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