Part- A: I. Answer ALL the following questions: 5 × 1 = 5 1. State Coulomb’s law in electrostatics. 2. What is the electric potential of the earth? 3. Draw a graph showing variation of resistivity of copper with temperature. 4. Mention the SI unit of magnetic field. 5. When does a charge moving in a magnetic field experience maximum force?
Part- B: II. Answer ANY TWO of the following questions: 2 × 2 = 4 6. Sketch the electric field lines due to a point charge q if (i) q < 0 and (ii) q > 0. 7. Give any two limitations of Ohm’s law. 8. Write any two uses of potentiometer.
Part- C: III. Answer ANY TWO of the following questions: 2 × 3 = 6 9. Show that the electric field at any point is equal to negative potential gradient at the point. 10. What is drift velocity? Write the expression for current in terms of drift velocity and explain the terms. 11. State and explain Biot-Savart’s law. 12. Obtain an expression for force experienced by a conductor carrying current placed in an external magnetic field.
Part- D: IV. Answer ANY TWO of the following questions: 2 × 5 = 10 13. State Gauss’s law in electrostatics. Obtain an expression for electric field at a point due to an infinitely long straight uniformly charged wire using Gauss’s law. 14. Derive an expression for electric potential at a point due to an isolated point charge. 15. Derive the condition for balance of a Wheatstone’s network using Kirchhoff’s laws. Name a device which works on the principle of balanced Wheatstone’s network.
