1. Define capacitance of a capacitor. Give its unit. Derive an expression for the capacitance of a parallel plate capacitor
in which a dielectric constant K ¡lls the space between the plates.
Or
Define the term of electric dipole moment . Give its unit. Derive an expression for the electric ¡eld intensity at any point
along the axial line of an electric dipole.
2. Describe principle, construction and working of a moving coil galvanometer. What is the importance of radial ¡eld?
Or
Compare dia, para and ferromagnetic materials on the basis of any ¡ve properties of these materials.
3. What is Self-induction? De¡ne self-inductance and calculate it for a long solenoid of length.
Or
Explain with the help of a diagram, the principle, construction and working of an a.c. generator.
4. State Huygen's principle and derive laws of refraction on its basis.
Or
Describe a compound microscope and ¡nd the expression for its magnifying power.
(SHORT ANSWER TYPE QUESTIONS)
5. De¡ne electric potential and deduce an expression for it due to a point charge at a distance r from it.
6. In a potentiometer, a cell of e.m.f. 12.5 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by
another cell and the balance point shifts to 63.0 cm. what is the e.m.f of the second cell?
7. Derive the relation R=ml/ne2Ar . Where symbols have their usual meanings.
8. Velocity of light in glass 2 x 108 m/s and in air is 3 x 108 m/s. If the ray passes through glass to air calculate the value
of critical angle.
9. Explain Polarisation by re¢ection. Deduce Brewster law.
10. Show that the de-Broglee wavelength of electron of energy E is give by relation.
11. De¡ne half-life of a radioactive sample. Deduce an expression for it.
12. Explain how junction diode is used as a full wave recti¡er.