Karnataka Board Class 12 Physics Sample Papers 2012

PHYSICS & CHEMISTRY
For Each multiple choice question four alternatives are given. Out of these alternatives choose the correct
Answer and write the answer in the space provided
 
1. Due to heavy traffic near the school the department of traffic police wants to install automatic traffic lights. This can be done by using the Principle of 1 x 10 = 10
a) Raman effect b) Radiography c) Holography d) Photoelectric effect
 
2. Water is to be sterilized for drinking purpose without using any chemicals this can be done by using
a) u v rays b) visible light c) short wave length radio waves d) long wave length Radio waves
 
3. In a heat engine the linear motion of the Piston is converted into rotation by the component
a) Spark plug b) Carburettor c) Crank shaft d) Fuel injection pump
 
4. An engineer wants to design an engine to convert 800KJ of heat into 840KJ of useful mechanical work.
The correct statement related to the above engine is that it
a) Is less efficient b) is more efficient c) cannot be designed d) is 100% efficient
 
5. An astrophysics Scientist observes that galaxy 'A' is more red shifted than galaxy 'B'. The conclusion
That can be drawn from this is that?
a) the velocity of 'A' is more than 'B' b) the velocity of 'B' is more than 'A'
c) both the galaxies have equal velocity d) both the galaxies are at rest.
 
6. In an nuclear reactor, the number of cadmium rods used are less than the required number. Then one of the possibilities is
a) the reactor may explode b) the chain reaction stops
c) number of fissions decrease d) the number of neutrons decrease
 
7. If emission test is required for an L.P.G run auto rickshaw, the availability of oxygen in moles for combustion of one mole of butane is
a) less than 5 b) between 8.5 and 9.5
c) between 9.5 and 10.5 d) more than 10.5
 
8. In a soap industry the chemist forgets to add sodium chloride during the manufacture of soap, the possible effect is
a) soap cannot be easily separated b) chemical composition of soap changes
c) soap will not get required colour d) the solubility of soap increases.
 
9. Borosilicate glass is used to make school laboratory equipments because it
a) is highly transparent b) with stands sudden changes in the temperature and transparent
c) has high refractive index d) absorbs radiations
 
10. Using sodium hydroxide as one of the raw materials it is possible to prepare
a) soaps and detergents b) cement and ceramics
c) glass and plastics d) cement and glass
.
Fill in the blanks with suitable terms
11. A p-n junction allows current to pass in one direction this is called_____ 1 x 3 = 3
 
12. Rader gun works on the principle of______
 
13. The device which converts light energy into electrical energy is______
 
14. Match the following
            Natural Gas                  LPG
            Butane                         Explosive
            Benzene                       to detect Leakage of Explosive
            Toluene                       Emission Test
                                                Carbon Black
                                                Perfumes
                                                Exhaust Gas
 
15. A cyclist going round a curve leans towards the centre of the curve. Give reason 1 x 6 = 6
 
16. What is a centrifugal governer?
 
17. What is the colour of the star Betelgeuse?
 
18. Mention the purpose of using a plane glass sheet in a solar cooker?
 
19. How does the pressure cooker help in saving energy?
 
20. Write the balanced chemical equation of the reaction between sodium carbonate and calcium chloride
 
21. Write any two factors on which the induced EMF depends 2 x 9 = 18
 
22. Draw a neat sketch of D.C. Dynamo
 
23. What is electromagnetic spectrum?
 
a) Name the electromagnetic radiations which has
1. the lowest frequency and
2. lowest wavelength
 
24. Draw a neat sketch to show the exhaust stroke of an external combustion engine
 
25. Give scientific reasons for the following
 
a) Iron articles are electroplated with chromium
b) Calcium silicate is a protective layer for the molten iron in the blast furnace
c) Copper is not used to prepare hydrogen in the laboratory
d) Ore of copper is not concentrated by hydraulic washing
 
26. What is the role of magnesium and dilute hydrochloric acid in the preparation of silicon
 
27. Write the steps involved in recycling plastics.
 
28. Name two types of hardness in water. On what principle can hardness of water be removed?
 
29. Draw a circuit symbol of each of the following
a) Forward biased diode b) transistors of n-p-n
 
30. State the universal law of gravitation. Prepare it by a mathematical equation 3 x 4 = 12
 
31. What is impure spectrum? Why is Raman scattering called incoherent and Rayleigh scattering called coherent scattering. On what basis did Raman give satisfactory explanation of incoherent scattering?
 
32. If the present mass of a radioactive element is 3.125 gm and its half life period is 8 days. What was its initial mass before 40 days.
 
33. Draw a neat diagram of the device that converts nuclear energy into electrical energy.
 
34. State the law of conservation of momentum. “The escape velocity on the earth is 4 x 3 = 12
11.2km/s” what does it mean? How are orbital and escape velocities related to one another? At what height geostationary satellite is launched.
 
35 How does a protostar attain the steady state? What is a neutron star?
 
36. Draw a neat diagram of each of the following
1. Blast furnace used to extract iron 2. Electrolytic refining of copper.