Question

A beaker contains water, initially at room temperature. It is continuously stirred until a hot object is immersed in it. Which one of the graphs best shows the temperature changes that follow?
Please give a reason for your choice as well.

Answer 1

I would go for D

as you stir the water, water gets heated up and when the object is put into the water, the object gets cooled down.

Also it cannot be A and C, cause at equilibrium the temperature of both object and water have to be equal.. Now the reason why it can't be B is because, initially water temp increases cause of stirring, later it increases cause of heat absorption from the object.. which cannot be linear.. hence it cannot be a straight line!

(also from newton's law of cooling, the rate at which the object cools or gains heat cannot be linear hence B is impossible) .. But there could be something that I am missing .. so feel free to express !

Answer 2

Shouldn't it be C? The temperature of water starts to increase while the object's temperature decreases until both reach thermal equilibrium. I was having trouble between A and C because both show the same concept somehow. But I don't know. You gave a totally different answer. >_<

Answer 3

Well if you see A and C, at thermal equilibrium, they are supposed to have the same temperature, but in those, the temperatures are not same!

Answer 4

unless you didn't draw them right :P!

Answer 5

Actually I am wrong, It can't be D, the temperature of water curve cannot an increasing exponential! :-/ m sorry :-/

Answer 6

Haha. I did draw them right. The book shows the same curves. They donot meet at a point.

Answer 7

C is correct, because when u extend the curve in (A), they cut and increase/ decrease futher...and c is correct , coz the constant temperature is shown...

Answer 8

Oh, thanks! :)