1 ) How much water a pump of 2kW can raise in one minute to a height of 10 m ? A ) 120 kg , B ) 1200 kg , C ) 2400 kg , D ) None of these ,

1 ) How much water a pump of 2kW can raise in one minute to a height of 10 m ?

A ) 120 kg ,                                      B ) 1200 kg , 

C ) 2400 kg ,                                    D ) None of these ,

Correct Answer : -   B ) 1200 kg , 

Solution : -

Given data : -

P = 2 kW = 2000 W ,

t = 1 minute = 60 seconds ,

h = 10 m ,

Formula : -

Here we have to find the mass ,

so first we will work : -

P = w / t ,

w = P x t = 2000 x 60 = 120000 J .

So now we can find mass : -

w = f . d  ,

w = (mg) . d ,

120000 = (m x 10 ) . 10 ,

m = 1200 kg ,  Answer  .

 

2 ) How do I calculate the electric power required to lift 100 kg of material of height  5 m and 2 mins ?

A ) 34 W  ,                                               B ) 41 W  ,

C ) 53 W  ,                                               D ) None of these ,

Correct Answer : -  B ) 41 W  ,

Solution : -

Given data : -

m = 100 kg ,

t = 2 mins = 120 secs ,

d = 5 m ,

g = 9.81 m / s² ,

P = ?

Formula : -

first we find force : -

F = mg = 100 x 9.81 = 981 N .

Now we find work : -

w = f . d ,

w = 981 x 5 = 4905 Nm or J .

Now we can power : -

P = w / t = 4905 / 120 = 41 W ,  Answer .

 

3 ) Sum of magnitude of two forces acting at a point is 16 N . If the resultant force is 8 N and its direction is perpendicular to smaller force , then forces will be : -

A ) 6 N  ,  12 N .                                           B ) 6 N  ,  10 N . 

C ) 8 N  ,  8 N .                                           D ) None of these ,

Correct Answer : -    B ) 6 N  ,  10 N . 

Solution : -

 

4 ) The maximum kinetic energy (K.E) of emitted photoelectrons depends on : -

A ) frequency of material ,                               B ) nature of material ,

C ) independent of intensity of light ,               D ) All of these ,

Correct Answer : - D ) All of these ,

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

UG Online quizzes