Qualification > Sciences
IGCSE PHYSICS
cooldude:
--- Quote from: @d!_†oX!© on November 07, 2009, 02:16:17 pm ---okay guys...another one...
A mercury thread of a thermometer is 12mm long when placed in melting ice, and 82mm long when placed in boiling water.
Find the:
a)length of the thread at 50oC
b)temperature when the length is 61mm long
plss guys, i need a full-fledged explanation for this cuz whenever i see this type of question after say 2-3 days, i tend to again do it wrong....plsss tell me a way to remember it forever....
Thanks guys!! :) :)
--- End quote ---
look adi we knw that b/w 12mm and 82mm lies 100.c. cuz melting point of ice=0 and boiling point of water=100. therefore in this scale 1mm=(82-12)/100
=>7/10=0.7
=>1.c=0.7mm
therfore at 50.c length=12+(0.7*50)=47mm
and then the next part=>
1.c=0.7mm
therefore the length for which there is a temperature change=>61-12=49mm
therfore the temperature at this=>49/0.7=70.c
just do it by simple unitary method
got it?
@d!_†oX!©:
see, acc. to u
0.7C - 1 mm
so 1C = 1/0.7 mm
so wt i didnt understand is y u did (50*0.7)
cuz 50 is the temp and 0.7 is also the temp at 1mm....so shudn't it be 50*0.7
bt if i do that den the answer is wrong....plsss dude tell me some way to get this thing rite into my head!!!
cooldude:
--- Quote from: @d!_†oX!© on November 07, 2009, 02:39:10 pm ---see, acc. to u
0.7C - 1 mm
so 1C = 1/0.7 mm
so wt i didnt understand is y u did (50*0.7)
cuz 50 is the temp and 0.7 is also the temp at 1mm....so shudn't it be 50*0.7
bt if i do that den the answer is wrong....plsss dude tell me some way to get this thing rite into my head!!!
--- End quote ---
dude 0.7 is not the temperature at 1 mm it is the value of the temperature of that changes for each increase in 1mm. theyve just given u 12mm-82mm to confuse u. this is the same as 1mm-70mm
cuz theyve started from 12 u hve to add 12 to (50*0.7), theres no hard nd fast way to answer it, uve gotta understand wat there askin and then answer accordingly
holychalice:
no it shud be 70
check again
@d!_†oX!©:
no dude...its 47mm nd 70C
nd cooldude...i'm kinda beginning to understand it now...
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