The percentage error in the measurement of mass and speed are 3% and 4% respectively . Then Maximum error in Kinetic energy will be ?

1 )  The percentage error in the measurement of mass and speed are 3% and 4% respectively .  Then Maximum error in Kinetic energy will be ?

A ) 9%  ,                                          B ) 11%  ,

C ) 15%  ,                                                D ) None of these ,

Correct Answer : -  B ) 11%  ,

Solution : -

Formula : -

We have formula for Kinetic energy is : -

K.E = (1/2)m(v^2)  , 

But for percentage error , it will write like this : -

∆k/k  =  (∆m/m) + 2(∆v/v)  ,  OR

∆k/k  =  3% + 2(4%)  =  11% .  Answer .

So percentage error will be 11%  .

 

2 ) If temperature in kelvin scale is reduced to half , then what would be effect on energy of radiations ?

A ) becomes 1/8^th ,                          B ) becomes 1/16^th ,

C ) becomes 1/32^th ,                                D ) None of these ,

Correct Answer : -  B ) becomes 1/16^th ,

Solution : -

 

3 ) The time period of same pendulum at karachi and murree is related as : -

A ) Tm > Tk  ,                                          B ) Tm < Tk  ,

C ) Tm = Tk  ,                                          D ) None of these ,

Correct Answer : -  A ) Tm > Tk  ,

Because  time period formula : -  T = 2 π√(L/g)  ,

So “g” at Karachi is greater than murree : -  gk > gm  

So by this time period at murree is more than Karachi : - Tm > Tk  ,

 

4 ) Child paradox is a consequence of …………. ( time dilation ) .

 

5 ) Capacitance in parallel plate capacitor : -  C = (AE˳) / d  .

When medium is placed in a capacitor : -  C = (kAE˳) / d  .

 

6 ) ( Mass spectrometer ) ………….  is used to measure the mass of a charge particle .

 

7 ) The bodies which fall freely under the action of gravity gives : -

A ) non uniform acceleration ,         B ) uniform acceleration ,

C ) constant acceleration ,                      D ) None of these ,

Correct Answer : -  B ) uniform acceleration ,

 

8 ) A man throws a ball vertically upward in a compartment of an accelerated train .  The ball will fall ………… ,

A ) in front of him     ,                               B ) behind him ,

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

Correct Answer : - B ) behind him ,

Because an accelerated train will go ahead of the ball and man is in motion with respect to train . And ball is also in motion but with respect to air .

 

9 ) The geostationary satellites are rotating around ……….. ,

A ) sun ,                                           B ) moon ,

C ) earth ,                                                D ) None of these ,

Correct Answer : -  C ) earth ,

 

10 ) SI units planks constant : -

A ) Js  ,                                            B ) J/s  ,

C ) J/s2  ,                                         D ) None of these ,

Correct Answer : -  A ) Js  ,

Solution : -

E = h f  ,

h = E / f  ,

h = J / (s^-1)  =  Js  .   Answer .

Now go to online quiz section and Physics Quiz 6 is uploaded related to these mcqs  , so check your preparation by this link : -

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