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7th August 2014, 01:23 PM
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| Re: CBSE Board Question Papers for Class 12th
Here I am giving you question paper for CBSE board of education class 12th science stream examination in PDF file attached with it . 3. State the condition under which a microwave oven heats up a food item containing water molecules most efficiently. 1 (41) 4. An electrical element X, when connected to an alternating voltage source, has the current through it leading the voltage by radii. Identify X and write an expression for its reactance. 1 5. A double convex lens, made from a material of refractive index , is immersed is a liquid of refractive index where . What change, if any, would occur in the nature of the lens? 1 6. The de Broglie wavelengths, associated with a proton and a neutron, are found to be equal. Which of the two has a higher value for kinetic energy? 1 7. Carbon and silicon are known to have similar lattice structures. However, the four bonding electrons of carbon are present in second orbit while those of silicon are present in its third orbit. How does this difference result in a difference in their electrical conductivities? 1 8. An unknown input (A) and the input (B) shown here, are used as the two inputs in a NAND gate. The output Y, has the form shown below. Identify the intervals over which the input ‘A’ must be ‘low’. 1 9. The two graphs drawn below, show the variation of electrostatic potential (V) with (r being distance of the field point from the point charge) for two point charges q1 and q2. The de Broglie wavelengths, associated with a proton and a neutron, are found to be equal. Which of the two has a higher value for kinetic energy? 1 Carbon and silicon are known to have similar lattice structures. However, the four bonding electrons of carbon are present in second orbit while those of silicon are present in its third orbit. How does this difference result in a difference in their electrical conductivities? 1     |