As physics p1 MCQS YEARLY ONLY.

[Jaf]

Jaf ibadsiddiqi Capricedcapri 1357913579 geek101 and every1 pleeeeeaaaaseeee
can someone urgently help with this?


View attachment 13034

1st one, in the center of the screen we know there will be a bright fringe. Also, the bright fringe happens because of constructive interference. The principle of superposition states that the total amplitude will be the sum of the individual amplitudes in a constructive interference and since both the waves have the same amplitude (coherent sources), the total amplitude is 2a.
So I/(2a)^2 = I1/a^2
I1 = (I a^2)/4a^2 = I/4

2nd one:
E = Fl/AΔl = Fl/l^2 x Δl
Now take the constants to the other side of the equation.
l/l^2 x Δl = E/F
1/l x Δl = E/F
1/Δl = El/F = kl (k = constant)
So we know the relationship is inversely proportional.

Note, you don't use 2F. This is because the other F may be taken as a reaction force. This of when you're compressing a spring on a flat table. You're applying a force on top and the table is also applying an equal force from the bottom. Even though two forces are acting, we take the 'load' as only the force we're applying.

Good luck!

 

[Soldier313]

geek101 @blood_mary Jaf ......thanx a million guys

 

[bloody_mary]

geek101 @blood_mary Jaf ......thanx a million guys

welcome

 

[Soldier313]

geek101 bloody_mary Jaf ......thanx a million guys

 

[Sanis]

GUYZ relax the exam is after several hours, studying now will confuse u and make it worse ..

 

[applepie1996]

GUYZ relax the exam is after several hours, studying now will confuse u and make it worse ..

wat variant r u guyz

 

[arlery]

GUYZ relax the exam is after several hours, studying now will confuse u and make it worse ..

I think going through them could help. I had a business exam yesterday so didn't have time to even look at Physics so just going through them now.
Oh and apologies to everyone for not completing Nov 09.

 

[ibadsiddiqi]

geek101 @blood_mary Jaf ......thanx a million guys

So sorry i cudnt reply earlier but im glad u got your answers!

 

[Soldier313]

@Jaf @ibadsiddiqi @Capricedcapri @1357913579 geek101 arlery
sorry for the bother...need some help here
ans is A for qn 1
ans is B fr qn 2
please can someone explainn

 

[arlery]

@Jaf @ibadsiddiqi @Capricedcapri @1357913579 geek101 arlery
sorry for the bother...need some help here
ans is A for qn 1
ans is B fr qn 2
please can someone explainnView attachment 13042View attachment 13043

In Q1
I think its A because P = VI
and V = I(R +r) where r is the internal resistance for the whole supply.
But here e have to take the load resistor's power so lets just go with the equation P =I^2 * R
So when R increases, P increases too, hence its A
Its not B because power is decreasing.
It can't be either C or D since the graph starts at zero which would be incorrect considering resistance changes frm 0.5 ohms to a higher value so power can not be zero.
Hope that clears it up!

 

[Soldier313]

In Q1
I think its A because P = VI
and V = I(R +r) where r is the internal resistance for the whole supply.
But here e have to take the load resistor's power so lets just go with the equation P =I^2 * R
So when R increases, P increases too, hence its A
Its not B because power is decreasing.
It can't be either C or D since the graph starts at zero which would be incorrect considering resistance changes frm 0.5 ohms to a higher value so power can not be zero.
Hope that clears it up!

thanx.......but then as u said as resistance increases power increases, thats nt true fr the whole graph
after lyk 2 ohms, it starts decreasing again.....:S

 

[arlery]

thanx.......but then as u said as resistance increases power increases, thats nt true fr the whole graph
after lyk 2 ohms, it starts decreasing again.....:S

Its not exactly decreasing, it becomes constant because the internal resistance of the supply is 2 ohms
and P max = when the internal resistance is equal to the resistance of the load.

 

[Soldier313]

Its not exactly decreasing, it becomes constant because the internal resistance of the supply is 2 ohms
and P max = when the internal resistance is equal to the resistance of the load.

thank you so much sis!
wen u get tym pls pls try to solve fr me the second one too....i'd really appreciate it
God bless you!

 

[arlery]

thank you so much sis!
wen u get tym pls pls try to solve fr me the second one too....i'd really appreciate it
God bless you!

You're welcome!
Erm I'm trying it but I just don't get it.
The only logic that comes to my mind is the sand starts falling at X so the sand starts falling at X so the frictional force causes v to decrease and since its constant, v at Y is same but I think I'm wrong. :$

 

[Soldier313]

You're welcome!
Erm I'm trying it but I just don't get it.
The only logic that comes to my mind is the sand starts falling at X so the sand starts falling at X so the frictional force causes v to decrease and since its constant, v at Y is same but I think I'm wrong. :$

no pro....thank you so much for helpin......

 

[Soldier313]

Going for my exam now....to all those who have helped me.....thanx soo much!
Wish you all g'luck...and inshaAllah we will all get straight As !

 

[arlery]

Going for my exam now....to all those who have helped me.....thanx soo much!
Wish you all g'luck...and inshaAllah we will all get straight As !

Best of luck!
In sha Allah!

 

[pearl angel]

this thread should be stickied for life!it helped so many people, future batches could benefit from it too

 

[Soldier313]

this thread should be stickied for life!it helped so many people, future batches could benefit from it too

totally agreed!

 

[madan159]

HELP NEEDED A balloon is rising vertically up with a velocity of 29m/s.A stone is dropped from it and it reaches the ground in 10s.The height of the balloon when the stone was dropped from it is (9 + 9.8m/s^2)