Physics problem.

[HamzaAsghar]

Hey could anyone explain the questions:
15
24
26

here is the link

http://www.xtremepapers.me/CIE/Cambridg ... _qp_12.pdf


I am very confused :fool:

 

[Usman17]

The answer to 15 would be D... Since you can see that at point X state is being changed. Water will solidify as its temperature decreases and since evaporation occurs at all temperatures so at X both solidification of WATER and evaporation wud be taking place...
Loll havent done concave lens... sorry

 

[BaKa]

15 is unclear so ill go with usman it might be D
24 well is should be a even though the image should be upright but still the image is real and magnified
26 is B for sure as earthing allows a huge current to pass while blowing the fuse so that electricity stops flowing to avoid shocks.

not clear about 15 though

 

[hussamh10]

A diverging lens alwayas forms diminished virtual and upright which is on the same side ans for 24 is D .

 

[Usman17]

24: I think the image formed cant be real in a concave lens... it has to be virtual..!!

 

[BaKa]

A diverging lens alwayas forms diminished virtual and upright which is on the same side ans for 24 is D .

LoL i merged it with another topic sorry everyone.
he is right the image formed by a diverging lens should be virtual diminished and upright.

 

[BaKa]

by the way i get it that it forms these images but then again which lens is used in cinemas?

 

[Maleeha]

by the way i get it that it forms these images but then again which lens is used in cinemas?

its not specifically cinemas i hv it written "for projector".. so i guess the same thng.. its convex lens.. converging , when object is placed between F and 2F
the image wud be beyond 2F on the other side and be real, inverted and magnified.

 

[HamzaAsghar]

for question 15 as at X the temperature is constant wouldn't evaporation cause the temperature to vary cause it causes
cooling???

 

[HamzaAsghar]

And for question 26 there is no mentioning of a fuse in the question??

And where can get images formed by diverging lens???

 

[abcde]

I found these useful notes for diverging lenses: http://www.physicsclassroom.com/class/refrn/u14l5ea.cfm
Btw, the correct option for 24 is B.

 

[HamzaAsghar]

I found these useful notes for diverging lenses: http://www.physicsclassroom.com/class/refrn/u14l5ea.cfm
Btw, the correct option for 24 is B.

By the notes it shows that the image is being magnified and not diminished

waisay thanks

 

[Maleeha]

it is being diminished.. the smaller one is image here and the one behind 2F is the object. diverging lens always diminishes the object..

 

[HamzaAsghar]

it is being diminished.. the smaller one is image here and the one behind 2F is the object. diverging lens always diminishes the object..

How does it diminish when it is spreading the rays :Search:

 

[Maleeha]

the image is formed where rays meet.. they spread on one side so will never meet there.. elongate the rays on the other side they'll meet and that would be the point image is formed at.. hope u get it.. see the notes again perhaps that would b helpful