1 ) Two springs of spring constant k1 and k2 at joined in series . Then effective spring constant of combination is ?

1 ) Two springs of spring constant k1 and k2 at joined in series . Then effective spring constant of combination is . . . . . . . . . . . . ?

Solution : -

Formulas : -

for parallel : -  ke = k1 + k2 + .......... ,

for series : - 1/ke = 1/k1 + 1/k2 + ....... ,

So , as by question ;

1/ke = 1/k1 + 1/k2 ,

so , ke = (k1 x k2) / (k1 + k2)  ,   Answer .

 

2 ) If earth is treated as a sphere of radius R and mass M , its angular momentum about axis of rotation with period T is . . . . . . . . . . ?

Solution : -

3 ) Moment of inertia depends on . . . . . . . . . . . . .  : -

A ) mass of body ,                           B ) axis of rotation ,

C ) shapes and sizes ,                             D ) All of these ,

Correct Answer  : -  D ) All of these ,

 

4 ) Product of uncertainty in positron and momentum is equals to . . . . . . . . . . . . . . ,

A ) kinetic energy ,                          B ) planks constant ,

C ) angular momentum ,                 D ) None of these ,

Correct Answer : -  B ) planks constant ,

Because  (∆P)  x  (∆X)  =  h  ,

And uncertainty in energy and time is also equals to planks constant  ,

(∆E)  x  (∆t)  =  h  ,

 

5 ) In the absence of external torques , the system total angular momentum will be : -

 A ) conserved ,                                               B ) non - conserved ,

C ) may A or B ,                                               D ) None of these ,

Correct Answer : -  A ) conserved ,

 

6 ) A couple produces . . . . . . . . . . . . . . . ( only rotational motion ) in the body .

A couple consists of two equal and opposite forces acting at a separation , so that net force  becomes zero .

Now go to online quiz section and Physics Quiz 9 is uploaded related to these mcqs  , so check your preparation by this link : -

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