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Applied Physics (Theory) 2010 Question Paper For CBSE Class XII Exams

Applied Phisics (Theory)

1. (a) State Gauss' theorem in electrostatics. Apply it to find the electric field strength at a point near a long straight conductor carrying electric charge. (6 Marks)
   OR
   What is the magnitude of a point electric charge chosen so that the electric field due to it at a point 50 cm away has magnitude 2.0 NC�� ? (6 Marks),
   
   (a) Derive a mathematical expression for the magnetic field strength at the center of a circular coil carrying electric current. (5 Marks)
   
   (c) Draw the electronic configuration in the atomic structures of 'Ge' and 'Si' atoms. How can these be made 'P-type' and 'N- type' semi - conductors? (4 Marks)
2. (a) Define the terms : 'magnetic field strength' , 'magnetic flux density' and 'permeability' of a manetic material. Write their SI units. (5 Marks)
   A current carrying conductor is placed at an angle of 30� to a uniform Magnetic field of strength 2�10� T. The length of the conductor inside the Magnetic field is 2 m and the current flowing through it is 1.6 A. Calculate the Magnitude of the force experienced by it.(5 Marks)
   (b) Distinguish between 'nuclear fission' and 'nuclear fusion'. Which one of them is Used for relese of energy in a nuclear reactor? Name one fuel used in a nuclear reactor. (6 Marks)
   (c) With the help of a circuit diagram, explain the working of a P-N-P transistor. (4 Marks)
3. (a) Define the term 'capacitance' of a capacitor. Derive an expression for the total Capacitance of 'n' capacitors arranged in series. (5 Marks)
   (b) Define the term 'capacitance' of a capacitor. Derive an expression for the total Capacitance of 'n' capacitors arranged in series. (6 Marks)
   (c) What are intrinsic and extrinsic semi - conductors? How does the rise in Temperature affects the conductivity of semi-conductors? (4 Marks)
   OR
   What is a P-N junction ? How does it behave under forward and reverse bias ? Explain with the help of circuit diagrams. (4 Marks)
4. (a) Define electric potential at a point due to a point charge. Write its SI unit. Derive an expression for the electric potential at a point outside a charged sphare. (5 Marks)
   (b) What are radiation hazards? Mention four safety measures which should be Taken against radioactive radiation. (6 Marks)
   OR
   What are radio isotopes? Write their any four uses. (6 Marks)
   (c ) Explain the working of a full wave rectifier using semi - conductor diodes, with the help of a labeled circuit diagram. (4 Marks)