Graded Discussion Board (GDB) for the course PHY101 (PHYSICS) will start on Wednesday 25th February 2015.
You should remember that you have to post your comments about the discussion title within the time.
This discussion board will be closed on Thursday 26th February 2015.
No comment about the Discussion topic should be posted on the regular Moderated Discussion Board which is created for each lecture.
The topic for the discussion is:
A room has one wall made of concrete, one wall made of copper, and one wall made of steel. All of the walls are the same size and at the same temperature of 20. Which wall feels coldest to the touch?
Select below the best choice according to your understanding and write the reason of your selected choice as well.
Elaborate your answer by giving a solid reason, give mathematical calculation (proof) where necessary.
Also you should remember that this Discussion is graded and maximum marks for this Graded Discussion Board 5% and it will count in your final Grade. So these marks may be helpful for you to get A grade from B and B grade from C and so on.
In the end you should also know that we will not extend the date of discussion in any case.
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میں تاریخ گزرنے کے بعد یہاں مکمّل اور مستند جواب شایع کروں گا
sir plz aj last date ha us GDB ka bara mai koi help ya hint dy dy plz
Heat aik khas kism ki energy hoti hae jo k high temperature se low temperature system ki tarf flow karti hae. esko flow of internal energy bhi kaha jata hae.
kisi bhi chiz ka garm ya sard hona oske heat capacity pe munhaser hae. koi jism garm ya sard tab hota hae jub oske under heat ko obsorb karne ki jitni salahiyat ho. agar woh ziada heat absorb karsakta hae to woh utna dair se garm ya thanda hoga.
pani m heat capacity sub se ziada hae. steel m 448 jab k copper m 387 joules per kg.Kelvin hae.
ooper diyi gaye options m copper sub se ziada thanda hoga pher steel aur akhair m concrete ki dewaar. concrete ki heat capacity 880 hae.
Copper is colder then others when we touch one of the walls, heat flows from our hands to the lower-temperature wall. The more rapidly heat flows from our hand, the colder we will feel. Recall that the rate of heat flow is proportional to the thermal conductivity. also that, copper has a much higher thermal conductivity (385.0W/m'K) than steel (50.2W/m'K) or concrete (0.8 W/m. K), and so the copper wall feels the coldest to the touch.
Q= kA (T hot - T cold) / L
when you touch one of the walls, heat flows from your hand to the lower-temperature wall. The more rapidly heat flows from your hand, the colder you will feel. Recall that the rate of heat flow is proportional to the thermal conductivity. Note also that, copper has a much higher thermal conductivity (385.0W/m'K) than steel (50.2W/m'K) or concrete (0.8 W/m. K), and so the copper wall feels the coldest to the touch. enjoy