Karnataka 2nd PUC PHYSICS (March, 2008) Question Paper

Karnataka Pre University Board 2nd year PHYSICS March, 2008 Question Paper.

Code No. 33

March, 2008

Time : 3 Hours 15 Minutes ] [ Max. Marks : 90

Note : i) Numerical problems solved without writing the relevant
formulae carry no marks.
ii) Answers without relevant diagram / figure / circuit wherever
necessary will not carry any marks.


I. Answer all of the following questions : 10 × 1 = 10

1. What is the deviation produced by a thin prism of angle 8° and of
refractive index 1·5 ?
2. Name a phenomenon which cannot be explained by considering light
as a wave.
3. Give an example for interference of light in a thin film.
4. Mention an example to show the importance of speed of light.
5. Write the formula for the capacitance of a spherical capacitor when
its outer conductor is earthed.
6. Define magnetic dip at a place.
7. What is the relation between 'r.m.s.' and 'average' value of sinusoidal
A.C. voltage ?
8. Give an example showing the conversion of energy into mass.
9. Which is the particle emitted along with electron when a neutron is
converted into proton in a nucleus ?
10. Write the circuit symbol of OR gate.


II. Answer any ten of the following questions : 10 × 2 = 20

11. What are the conditions for a pair of thin prisms to produce
dispersion without deviation ?
12. Draw the neat diagram of experimental set-up for Fraunhofer
diffraction at a single slit.
13. What are elliptically polarised and circularly polarised lights ?
14. State Coulomb's law and define unit charge.
15. An electric dipole of moment 2 × 10 – 8 coulomb-m is placed in an
electric field of 5 × 10 – 5 NC – 1 , with its axis making an angle of 30°
with the field. What is the torque acting on the dipole ?
16. What is superconductivity ? Define critical field.
17. State and explain Kirchhoff's first law of electrical network.
18. Express Laplace's law in mathematical form and explain the symbols.
19. Name any two advantages of A.C.
20. What is 'Raman effect' ? What type of scattering is it ?
21. Mention any two properties of LASER beam.
22. What is a photodiode ? In which biasing does it work ?


III. Answer any one of the following questions : 1 × 5 = 5
23. Derive an expression for 'Lateral Shift' produced when a ray of light
passes through a parallel sided glass slab.
24. i) Write any three differences between 'Ordinary ray' and
'Extraordinary ray'.
ii) Mention any two applications of polaroids.

IV. Answer any two of the following questions : 2 × 5 = 10

25. Define e.m.f. and internal resistance of a cell. Obtain an expression
for current in a simple circuit consisting of a cell and an external
resistance using Ohm's law.
26. Give the theory of moving coil galvanometer.
27. i) Explain the principle of Dunnington's method of finding
m of
an electron.
ii) Write Einstein's photoelectric equation. Using that explain any
two experimentally observed facts about photoelectric effect.
V. Answer any two of the following questions : 2 × 5 = 10
28. i) Explain nuclear fusion with an example.
ii) What is the principle of a nuclear reactor ? Mention any two
methods of disposal of nuclear waste.
29. Define decay constant and half-life of a radioactive substance. Derive
an expression for half-life in terms of decay constant.
30. With a circuit diagram, explain the action of a npn transistor as an
amplifier in CE mode.

VII. Answer any one of the following questions : 1 × 5 = 5

35. Describe an experiment to determine the dispersive power of the
material of a prism for any two colours ( Assume that the angle of
prism is given ).
36. Describe an experiment to draw the forward bias characteristics of a
semiconductor diode and hence to determine forward bias

VIII. Answer any one of the following questions : 1 × 5 = 5

37. The following readings were observed while determining the
temperature coefficient of resistance of a thermistor using metre
( °C )
Resistance in
right gap ( Ω )
length ( m )
30 150 0·525
35 150 0·479
Calculate the temperature coefficient of resistance of the thermistor. 15 Code
38. Determine the current sensitivity of a pointer galvanometer from the
following observations recorded in an experiment :
Resistance of galvanometer = 100 Ω
e.m.f. of the cell = 1·5 V
Trial No. r ( Ω ) R ( Ω ) θ ( div )
1 1 40 22
2 1 55 16
3 1 74 12
( Note : Galvanometer is connected across r )


IX. Answer any one of the following questions : 1 × 10 = 10

39. a) In Young's double-slit experiment distance between the slits is
1 mm. The fringe width is found to be 0·6 mm. When the
screen is moved through a distance of 0·25 m the fringe width
becomes 0·75 mm. Find the wavelength of the light used. 4
b) Define electric intensity and electric potential. Obtain the
relation between them. 4
c) Write the expression for resolving power of a microscope and
explain the terms. 2


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