Subject

Physics

Class

ICSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
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 Multiple Choice QuestionsShort Answer Type

41. Alpha particles having kinetic energy of 1.8 MeV each are incident on a thin gold foil, form a large distance. Applying the principle of conservation of energy, find the closest distance of approach of the alpha particle from the gold nucleus. 
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42. Calculate the minimum wavelength of X rays emitted by an X ray tube operating at a tube potential of 40 kV. How will this wavelength change if target is made of another metal ?


Wavelength is given by, 


straight lambda subscript straight m space equals space hc over eV
Here, 

V = 40 kV = 40 x 103 V

Therefore, 

straight lambda subscript straight m space equals space fraction numerator hc over denominator ex 40 space straight x space 10 cubed end fraction

space space space space equals space fraction numerator 6.6 space straight x space 10 to the power of negative 34 end exponent space straight x space 3 space straight x space 10 to the power of 8 over denominator 1.6 space straight x space 10 to the power of negative 19 end exponent space straight x space 40 space straight x space 10 cubed end fraction

space space space space equals space fraction numerator 6.6 space straight x space 3 space straight x space 10 to the power of negative 15 end exponent space straight x space 10 to the power of 5 over denominator 1.6 space straight x space 40 end fraction

space space space space equals space fraction numerator 6.6 space straight x space 3 over denominator 1.6 space straight x space 40 end fraction space straight x space 10 to the power of negative 10 end exponent

space space space equals space fraction numerator 19.8 space over denominator 64 end fraction space straight x space 10 to the power of negative 10 end exponent space

space space space equals space 0.309 space straight x space 10 to the power of negative 10 end exponent

straight lambda subscript straight m space equals space 3.09 space straight x space 10 to the power of negative 11 end exponent space straight m space equals space 0.0309 space nm

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43. Draw a rough sketch showing the variation of binding energy per nucleon with mass number of various nuclei. Label the graph and state the region where the nuclei are most stable.
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44. Draw a labelled circuit diagram of a N-P-N transistor in a common-emitter configuration to study its characteristics. 
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45. Why is a NAND gate called a universal gate ? Show how an AND gate can be obtained using one or more NAND gates.  
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 Multiple Choice QuestionsLong Answer Type

46. In the circuit given below, E1 and E2 are two cells of emfs 4 V and 6 V respectively, having negligible internal resistances. Applying KirchofFs laws of electrical networks, find the values of I1 and I2



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47. A 30 mF capacitor, 0.2 H inductor and a 50 Ω resistor are connected in series to an A.C.


source whose emf is given by E = 310 Sin (314 t) where E is in volt and t is in second. Calculate:  

(i) the impedance of the circuit and

(ii) peak value of current in the circuit. 

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