West Bengal Board Model Questions & Answers : Class-12 Physics

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West Bengal Board Model Questions & Answers : Class-10

 

Exam Name :  West Bengal Board Model Questions & Answers

Subject : Physics (Model Paper's I,II,III & IV)

Class : 12

Model Question Physics − 3

Kanak Ranjan Tola

Ballygunj Govt. High School

Group A

Give answers to the following questions either in      one word    or one sentence.

(Alternatives are to be noted):                                                                         1 x 10 = 10

       1.(a)    ‘A progressive wave carries energy in a plane perpendicular to the  plane of wave front’ −− is the statement true      

       Ans:    The statement is not true.

          (b)       Beats will be audible if the difference in frequencies  of two superposing waves is not greater than.........                                                           1

       Ans:    Beats will be audible if the difference in frequencies  of two superposing waves is not greater than     15     .

   (c)       The value of potential inside a hollow spherical conductor is ......................  1

Ans:    The  value  of  potential inside  a  hollow  spherical conductor  is

 

 

R= radius of the conductor.

 

(d)

Can it be possible to accelerate a neutron in a cyclotron accelerator ?

1

Ans.

 

(e)

It is not possible to accelerate a neutron in cyclotron accelerator.

 

Comment whether P−type semiconductor is positively charged or not ?

 

 

1

Ans.

 

(f)

P−type semiconductor is not charged.

 

Give an example where electron ejects photon.

 

 

1

Ans.

In X−ray production electron ejects photon.

 


Group B

2. (a)   Why centrifugal force is termed as pseudo force ?                                       2

            Ans.    There is no existence of centrifugal force in an inertial frame of reference. The source of this force in a noninertial frame, cannot be find out.             It appears not due to action−reaction like seal force. So it is termed as pseudo force.

           (b)        Degree of freedom of molecules of a gas is 5. Find the value of Cp  / Cv    

 

Courtesy: West Bengal Board