Physics: Post your doubts here!

[Snowysangel]

Is the formula intensity=power/area in the as syllabus?

 

[Browny]

Is the formula intensity=power/area in the as syllabus?

I haven't found that in papers but it was in the the physics AS and A Level Coursebook.

 

[Browny]

Can anyone tell me whether in theory papers they will cut marks for significant figures because sometimes it is to 2 and sometimes 3. Sometimes when the data is to 2 s.f. even the answers are to 3 s.f?

 

[Zepudee]

View attachment 41690

Thank you!

 

[zem]

Can someone help me with c part of this question?

 

[Thought blocker]

Can someone help me with c part of this question? View attachment 41777View attachment 41778

Lowest frequency will be the distance b/w node to anti node that is we no lambda/4..
So as we know L = 0.45 ; 0.45 = Lambda / 4 ; Lambda = 1.8 (Length = lambda / 4 used here)
Now, V = f * lambda ---> 330/1.8 is about 180 Hz

 

[Tulaib]

Someone help me with Q4(b)

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_22.pdf

 

[Snowysangel]

Can someone help me with c part of this question? View attachment 41777View attachment 41778

For b(ii) we take L as 60 cm right?

 

[Snowysangel]

Someone help me with Q4(b)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_22.pdf

The elastic potential energy is the energy under the graph. You count the number if small squares and multiply it by the area of one small square to find out the energy. The wire will be permantly stretched/extended a little since some if the energy has been converted into its inter al energy which has increased the spacing between its atoms and has hence permantly deformed it

 

[Tulaib]

The elastic potential energy is the energy under the graph. You count the number if small squares and multiply it by the area of one small square to find out the energy. The wire will be permantly stretched/extended a little since some if the energy has been converted into its inter al energy which has increased the spacing between its atoms and has hence permantly deformed it

which graph should we consider for it? upper or lower?

 

[Snowysangel]

which graph should we consider for it? upper or lower?

Upper minus lower. The upper graph represents the energy absorbed by the wire to cause its extension l. The lower one represents the energy released by the wire to bring it back to its original position. But it doesn't return to its original position and the extra energy is stored as the wires internal energy or its elastic potential energy

 

[zem]

For b(ii) we take L as 60 cm right?

Emm no actuall y 45 i guess because its 3/4 of the wave

 

[zem]

Lowest frequency will be the distance b/w node to anti node that is we no lambda/4..
So as we know L = 0.45 ; 0.45 = Lambda / 4 ; Lambda = 1.8 (Length = lambda / 4 used here)
Now, V = f * lambda ---> 330/1.8 is about 180 Hz

Is the lowest frequency always between the node and antinode?

 

[zem]

Lowest frequency will be the distance b/w node to anti node that is we no lambda/4..
So as we know L = 0.45 ; 0.45 = Lambda / 4 ; Lambda = 1.8 (Length = lambda / 4 used here)
Now, V = f * lambda ---> 330/1.8 is about 180 Hz

and yes thankyou by the way

 

[Snowysangel]

Emm no actuall y 45 i guess because its 3/4 of the wave

But how do we know its in the piston is in that position in the figure?

 

[Snowysangel]

Is the lowest frequency always between the node and antinode?

When a loud sound is heard

 

[zem]

But how do we know its in the piston is in that position in the figure?

I got no idea im confused!

 

[Snowysangel]

Hey on the surface of the earth, the gravational force of the earth on a man and the gravational force if the man on the earth ate equal rifht according to newtons third law, but as he goes up doesnt the gravational force of the man on the earth become greater than the gravational force of the earth on the man? I'm cleerly REALLY confused

 

[princeali97]

Suggest why a thin rod can bend more than a thick rod without breaking.
Explanation required.Thanks in advance.

 

[Snowysangel]

Suggest why a thin rod can bend more than a thick rod without breaking.
Explanation required.Thanks in advance.

Cause in a thick rod both the sides have different extensions so it creates added stress on the rod which cause it to break