ANSWER KEY HSEB 2070[2013]

                                        PHYSICS. SUB. CODE 110' D'

                                                                                                                                                                                                                       

                                                 GROUP 'C'

 9 Q.( a)     F=7.2 N and F =8.28 N

       (b)     n =67.5 rpm

       (c)     w =8.35 x 10^-3 J

       (d)     v =3.77 m / s and  a =94.6 m /s²

 10 Q .(a)    c =528.57 J/kg /k

         (b)    k= 178.34 w /m/k or, k= 0.42 cal /s /cm/⁰C

         (c)     Efficiency (n) =30 %

 11 Q  angle =0.0091 radian

 12 Q.  V =604 v and E=1.2 x 10⁵ v/m

         

 

 Most probable questions for preparation of physics class 12th. 2070(2013);

                             MODERN PHYSICS 

 

1Q. Write down the postulates of Bohr's model of  hydrogen atom. Obtain an expression for energy of the n th

orbit of electron.

 2Q. Discuss necessary theory of J.J.Thomson's method to determine the specific charge(e/m) of an electron.

3Q. Write down laws of radioactive disintegration.Obtain an expression for exponential decay law and hence derive an expression for half life.

 

4Q. What do you mean by zener diode? How can this be used as voltage regulator.

 

5Q Describe the production and properties of x-rays.

      Discuss diffraction of x-rays and derive Bragg's laws.

6Q.What is photoelectric effect. Discuss Einstein's photoelectric equation and verify it.

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Last year questions may repeat

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 Millikan's oil drop expt.

Full wave rectifier and filter circuit.

He-Ne laser

Nuclear fission and nuclear fusion. Energy released in such

  process.

Transistors and characteristics curves.

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..sparkling topics.............

7Q.Water pollution

      Air pollution

       Energy crisis

      Energy sources of Nepal

      Quarks model

      Logic gates

     Junction diodes in forward and reverse bias

     Mass defect and Binding energy.

     properties of alpha, beta and gamma particles.

 

 

 

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