Physics: Post your doubts here!

[Thelastmoment]

Q33 Needs an explanation. Answer is A.

 

[amina1300]

Q33 Needs an explanation. Answer is A.

R= pL/A and Ohms Law V=IR hence the thickest conductor has the least resistance so the smallest Voltage drop across the thickest conductor.A is answer. The potential drop with distance is represented by grad of graph so the value of the grad drop should be the smallest for the thickest conductor Since thre is a potential drop gad is -ve.

 

[Thelastmoment]

R= pL/A and Ohms Law V=IR hence the thickest conductor has the least resistance so the smallest Voltage drop across the thickest conductor.A is answer. The potential drop with distance is represented by grad of graph so the value of the grad drop should be the smallest for the thickest conductor Since thre is a potential drop gad is -ve.

Thanks a lot.

 

[Holmes]

Help !

 

[Thelastmoment]

Thanks a lot.

 

[Thelastmoment]

View attachment 62308

Help !

Hope it helps

 

[amina1300]

Post the hardest MCQs !!

 

[Holmes]

Hope it helps

Thank you !Thelastmoment

 

[Holmes]

Post the hardest MCQs !!

Here you go


thanks in advance

 

[Holmes]

Post the hardest MCQs !!

 

[Holmes]

Post the hardest MCQs !!

 

[amina1300]

Here you go
View attachment 62310
thanks in advance

The first one was a bit tricky the others were easy.

Do u want me to show you how I got the answers?

Thanks for posting btw.

 

[amina1300]

Post the MCQs you found the hardest! I want to solve them for practice

 

[dumbledore.]

In one such pump the long approach pipe holds 500kg of water. A valve shuts when the speed of
this water reaches 2.0ms–1 and the kinetic energy of this water is used to lift a small quantity of
water by a height of 15m.
The efficiency of the pump is 10%.
Which mass of water could be lifted 15m?
A 0.15kg B 0.68kg C 1.5kg D 6.8kg

 

[Thelastmoment]

In one such pump the long approach pipe holds 500kg of water. A valve shuts when the speed of
this water reaches 2.0ms–1 and the kinetic energy of this water is used to lift a small quantity of
water by a height of 15m.
The efficiency of the pump is 10%.
Which mass of water could be lifted 15m?
A 0.15kg B 0.68kg C 1.5kg D 6.8kg

Answer:

I guess,
K . E= 1/2 x m x v2(squared)
= 1/2 x 500 x 2 (2)
=1000 J

then,
G.p.e = mgh
re-arrange to
m= G.p.e/( g x h)
=1000J / (9.81 x 15 )
= 6.8kg


6.8kg for 100%
m1 kg for 10%
cross multiply to get 0.68kg so answer is B.

 

[Bishnu Dev]

Solve this please... Answer is C. I get A

 

[Bishnu Dev]

Here you go
View attachment 62310

thanks in advance

answer is C for 13? Which year paper is this and what is the component code? I got 'C' for the question number 28 as well and 'B' for question number 10.

 

[amina1300]

answer is C for 13? Which year paper is this and what is the component code? I got 'C' for the question number 28 as well and 'B' for question number 10.

Your right, and this is March 2017.

 

[amina1300]

Solve this please... Answer is C. I get A

You get diameter 4.81mm so for radius d/2 and convet mm to m.
In m 4.81/2/1000
Next u find the volume using 4/3pi r^3
Density =mass(kg)/volume(m^3)
Convert g to kg 0.450/1000 ÷vol and you get C as the answer.

 

[amina1300]

que no 13 and 14 as well please

Q13 F1d1 + F2d2 =Ftdt
16000*0.6 +9000*2.1 =(16000+9000)*
28500÷2500=s
d=1.14m