Physics: Post your doubts here!

[dwightedknight]

2(x+5) + 1 = 7 + 2x. Please help.

 

[A*****]

Why can't it be B or C?

 

[A*****]

2(x+5) + 1 = 7 + 2x. Please help.

What is this??

 

[Mush999]

2(x+5) + 1 = 7 + 2x. Please help.

This equation is not correct I guess, there's no solution. Is there a question about it?

 

[Mush999]

View attachment 64101

Why can't it be B or C?

Because area under Force extension graph is always the work done in stretch the wire, given no plastic deformation has occurred. If plastic deformation occurs then the area under the graph beyond yield point, is the energy used to permanently deform the wire
t
Not B because the wire is extended plastically and it will not go back to it's original lenght, so the energy is use up in misplacing the atoms in the structure of the wire

Not C because the first part of the graph where the wire extends elastically, the energy is used strechs the wire not deform it permanently thus no heat.

D is the right option

 

[A*****]

Why can't it be C??

 

[dwightedknight]

This equation is not correct I guess, there's no solution. Is there a question about it?

Oh there is not solution. I got confused.

 

[dwightedknight]

View attachment 64102

Why can't it be C??

It's a slight inaccuracy from CIE I believe. Instead of "infinite", you should interpret as "very large".

 

[Mush999]

View attachment 64102

Why can't it be C??

That's a galvenometer and it a very sensitive device, upto 0.001A
Ita resistance is almost negligible!

The correct answer is B!

 

[A*****]

It's a slight inaccuracy from CIE I believe. Instead of "infinite", you should interpret as "very large".

There is no problem with the word 'infinite' but I just wanted to ask that why this option is not correct although it is possible

 

[A*****]

That's a galvenometer and it a very sensitive device, upto 0.001A
Ita resistance is almost negligible!

The correct answer is B!

Ohh right!

 

[A*****]

How to do this? I did it just by comparing their units but I want a proper method if anyone could help plz

 

[Kanekii]

Is it D?
If so then:
The equation used will be F=ma, Density=M/V and v=s/t
so M=Density*(A*s/t)
M=kgs-1
F=M*v
F=kgms-2
F=Density*A*v^2

 

[hellodjfos;s'ff]

View attachment 64102

Why can't it be C??

Can't be C, because if the resistance was infinite, the ammeter would show an error sign. If the pd is zero between the two points, then the ammeter would show zero since no current would flow between those point.

 

[A*****]

Is it D?
If so then:
The equation used will be F=ma, Density=M/V and v=s/t
so M=Density*(A*s/t)
M=kgs-1
F=M*v
F=kgms-2
F=Density*A*v^2

Thankss!!

 

[hellodjfos;s'ff]

How to do this? I did it just by comparing their units but I want a proper method if anyone could help plz

View attachment 64103

I think there are about 3 methods to attempt this one.
P=pgh, P=F/A
F=P*A
F=pgh*A
g*h becomes v^2(their units multiply to form the units of v^2).
F=p(v^2)(A) which is D

2nd method:
F=mv/t, p=m/V, v=l/t
p=m/V becomes m=p*V
Replace m=p*V into F=mv/t
F=p*V*v/t
V can be broken up into A and l(area and length)
F=p*A*l*v/t
l/t=v, so:
F=p*A*v^2

 

[Ayesha_m01]

 

[hellodjfos;s'ff]

Intensity is directly proportional to amplitude squared.
The equation becomes I=A^2/x^2 which can be simplified to I=A/x
At P: I=8/1 so intensity at P is 8 micro meter
At Q: I=8/2 so intensity at Q is 4 micro meter(D)

 

[Ayesha_m01]

Intensity is directly proportional to amplitude squared.
The equation becomes I=A^2/x^2 which can be simplified to I=A/x
At P: I=8/1 so intensity at P is 8 micro meter
At Q: I=8/2 so intensity at Q is 4 micro meter(D)

may god bless you

 

[Hisham Khan]

Help?