Yatayyat
Badges: 14
Rep:
?
#1
Report Thread starter 2 years ago
#1
How would I do this MCQ?

You have to find the ratio between SHC and SLH?


But I’m not exactly sure how to pick up the value that is needed to plug into the formula?

Name:  643BF8BF-E479-44BD-A6E8-3B6D95ED3C22.jpg.jpeg
Views: 74
Size:  13.0 KB

Thanks
0
reply
isiaiah d
Badges: 18
Rep:
?
#2
Report 2 years ago
#2
(Original post by Yatayyat)
How would I do this MCQ?

You have to find the ratio between SHC and SLH?


But I’m not exactly sure how to pick up the value that is needed to plug into the formula?

Name:  643BF8BF-E479-44BD-A6E8-3B6D95ED3C22.jpg.jpeg
Views: 74
Size:  13.0 KB

Thanks
You have to assume the power stays constant so:
Q/T = mC^T/t and

^T/t=2 so Q/T = 2Mc = P

Also Q=Ml and P=Ml/t = 2Mc time for solidification is 20 minutes

l/20 = 2cso c/l=1/40
1
reply
Yatayyat
Badges: 14
Rep:
?
#3
Report Thread starter 2 years ago
#3
(Original post by isiaiah d)
You have to assume the power stays constant so:
Q/T = mC^T/t and

^T/t=2 so Q/T = 2Mc = P

Also Q=Ml and P=Ml/t = 2Mc time for solidification is 20 minutes

l/20 = 2cso c/l=1/40
I’m confused to what formula you are even using? Is it Q = mc delta T and Q = ML?
0
reply
Eimmanuel
Badges: 13
Rep:
?
#4
Report 2 years ago
#4
(Original post by Yatayyat)
How would I do this MCQ?

You have to find the ratio between SHC and SLH?


But I’m not exactly sure how to pick up the value that is needed to plug into the formula?

Name:  643BF8BF-E479-44BD-A6E8-3B6D95ED3C22.jpg.jpeg
Views: 74
Size:  13.0 KB

Thanks
Assume the rate of heat loss is constant and let rate of heat loss be P.

When the liquid is cooling, the rate of heat loss is

 P = m \times c \times \dfrac{ \Delta \theta}{\Delta t}

When the liquid is solidifying, the rate of heat loss is

 P = \drac{m \times L \times}{\Delta t}

Equate the two equations and you can find the required answer.
0
reply
Yatayyat
Badges: 14
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by Eimmanuel)
Assume the rate of heat loss is constant and let rate of heat loss be P.

When the liquid is cooling, the rate of heat loss is

 P = m \times c \times \dfrac{ \Delta \theta}{\Delta t}

When the liquid is solidifying, the rate of heat loss is

 P = \drac{m \times L \times}{\Delta t}

Equate the two equations and you can find the required answer.
Shouldn't the second equation you put in be 'P = (M*L) / delta t, since power is the energy transferred per unit time
0
reply
Eimmanuel
Badges: 13
Rep:
?
#6
Report 2 years ago
#6
(Original post by Yatayyat)
Shouldn't the second equation you put in be 'P = (M*L) / delta t, since power is the energy transferred per unit time
Yes, indeed. There are some typo in the tex.

P = \drac{m \times L \times}{\Delta t}

The correct tex should be

 P = \dfrac{m \times L }{\Delta t}
0
reply
Yatayyat
Badges: 14
Rep:
?
#7
Report Thread starter 2 years ago
#7
Makes sense now. Cheers for all the help given.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Have you experienced financial difficulties as a student due to Covid-19?

Yes, I have really struggled financially (56)
17.28%
I have experienced some financial difficulties (92)
28.4%
I haven't experienced any financial difficulties and things have stayed the same (121)
37.35%
I have had better financial opportunities as a result of the pandemic (44)
13.58%
I've had another experience (let us know in the thread!) (11)
3.4%

Watched Threads

View All