Rajasthan Board Senior Secondary Examination 2010 – Physics Paper I

1. (i)A graph between potential ( V ) and charge ( q ) of an isolated sphere is shown in figure. Capacitance of the sphere will be

(A) sin θ                               (B) cos θ
(C) tan θ                               (D) cot θ.                               1/2

(ii) The resistance temperature coefficient of the material used for potentiometer wire should be

(A) high                                (B) low
(C) zero                                (D) infinite.                           1/2

(iii) Magnitude of the horizontal component BH and vertical component BV of the earth’s magnetic field at a place are equal.Value of the total intensity of earth’s magnetic field at that lace is

(A) B H                                   (B) 2 BH
(C) √2BH                               (D)BH/2 .                             1/2

(iv) The current passing through an a.c. circuit is I = 5 cos ωt ampere and potential difference is V = 20 sin ωt volt. The power loss in watt will be

(A) zero                                    (B) 10
(C) 5                                           (D) 100.                              1/2

2. Write the names of two substances, whose resistivity decreases on raising temperature. 1/2

3. Write the value of neutral temperature ( Tn ) for Cu – Fe thermocouple. 1/2

4. Write down Curie’s law. 1/2

5. Write down the formula of magnetic energy stored in a coil of self inductance L, when I 0 current is passing through it. 1/2

6. (i) Define relative permittivity. 1/2

(ii) Write down the value of dielectric constant of copper. 1/2

7. What is an equipotential surface ? Draw diagram to show equipotential surface due to a positive point charge. 1/2 + 1/2 = 1

8. Write one difference between the terminal voltage and electromotive force of a cell. 1

9. In figure, a meter-bridge is shown in its balance position. Find the value of unknown resistance ( X ).

10. If a bar magnet is divided in two equal parts along perpendicular to its axis then how does (i) pole strength and (ii) magnetic moment of bar magnet change ?1/2 + 1/2 = 1

11. A toroid of mean radius 10 cm has 1000 turns. When 0·1 ampere current is passing through it, calculate magnetic field on its axis. 1

12. (i) Write down tangent law.1/2

(ii) Write down the unit of the reduction factor of tangent galvanometer.1/2

13. Lenz’s law is in accordance with the law of conservation of energy.Explain. 1

14. An electron is orbiting around an infinite positive line charge in a cycle of radius 0·5 metre. If the linear charge density is 18·2 × 10 ^– 10 coulomb/metre, then calculate the speed of lectron( in m/s ). ( Mass of electron m e = 9·1 × 10^ – 31 kg ) 2

15. In the following figure, a circuit of an infinitely long series network of resistors is shown. Find the equivalent resistance of network between the points A and B, when R 1 = 1 Ω and R   = 2 Ω : 2

16. Derive the formula to determine the internal resistance of a cell by Mance’s method. Draw the necessary circuit diagram. 1 1/2+ 1/2 = 2

17.What do you mean by thermo-current ? How does the value of thermo e.m.f. change with the temperature ? Explain and draw the graph.1/2 +1+1/2= 2

18. Establish the relation between relative magnetic permeability ( μ r ) and magnetic susceptibility ( x ). 2

19. Obtain an expression for the self inductance of a long solenoid. Draw the necessary diagram. 1 1/2+ 1/2= 2

20. At any time t in an a.c. circuit, potential is V = 200 sin 157t cos 157t volt, and current is I = sin ( 314t + π/3) ampere. In this case calculate :

(i) frequency
(ii) root mean square value of voltage
(iii) impedance of circuit
(iv) power factor.1/2+ 1/2+ 1/2+ 1/2= 2

21. Find the root mean square ( r.m.s. ) value of sinusoidal alternating current I = I 0 sin ωt for a complete cycle. 2

22. Explain the principle of capacitor. Derive the expression for capacity of a spherical capacitor. Draw the necessary diagram. Draw a graph between radius and capacity of spherical  conductor

23. Define electric dipole. Derive the expression for the electric field intensity at a point on the equatorial line of an electric dipole. Draw the necessary diagram. If the potential is  constant in a field then what will be the electric field intensity ? 1/2+ 2 + 1 + 1/2= 4

OR

Define electric potential. Derive an expression for the electric potential at a point ( r, θ ) due to electric dipole. Draw the necessary diagram. Find electric potential on equatorial line of electric dipole.1/2+ 2 + 1 + 1/2= 4

24. State Biot-Savart’s law. Derive the expression for the magnetic field at an axial point of a circular current carrying coil. Draw the neessary diagram. 1 + 2 + 1 = 4

OR

State Ampere’s law. Derive the expression for magnetic field due to long solid cylindrical current carrying conductor at a point located (i) outside and (ii) inside the conductor. Draw necessary diagram.

1 + 1 + 1 + 1 = 4