00:01
Hello.
00:03
The question here is, a 0 .4 kg sample is placed in a cooling apparatus that removes energy as heat at a rate, constant rate.
00:13
The figure gives the temperature t of the sample versus the time t.
00:18
The horizontal scale is set by t .s.
00:21
Is equal to 80 minutes.
00:23
The sample freezes during the energy removal.
00:28
The specific heat of the sample in its initial phase.
00:31
Is given as 3 ,000 joules per kg kelvin.
00:36
What are the samples heat of fusion? so in this question, it is given that the mass of the sample is 0 .4 kg.
00:46
The time is t .s which is given as 18 minutes.
00:51
And the specific heat of the sample in its liquid phase is 3 ,000 joules per kg kelvin.
00:57
Now we can see in the figure that there is a temperature reduction from 300 to 270 and after that it is constant for some time and then from 270 to it reduces to 250 now we need to calculate the heat of fusion so for that first we'll calculate the change in temperature so the changing temperature which is given by modulus of delta t is equal to t2 minus t1 modulus which will be equal to modulus of 300 minus 270.
01:40
So change the temperature, delta in modulus is 30 degree...