Specific heat capacity & heat capacity

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Homework Help Overview

The discussion revolves around the concepts of specific heat capacity and heat capacity, focusing on a problem that involves calculating a ratio between these two quantities. Participants express confusion regarding the dimensions and definitions associated with the terms.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question the dimensionality of the ratio and whether a dimensionless value can be assigned. There is also confusion about the definitions of specific heat capacity and heat capacity, leading to discussions about their respective formulas and the implications of the question being ill posed.

Discussion Status

Some participants have provided clarifications regarding the definitions and relationships between specific heat capacity and heat capacity. There is ongoing exploration of how to interpret the question correctly, with no explicit consensus reached on the correct approach.

Contextual Notes

Participants note that the question may contain distractors and unnecessary information, which complicates the identification of relevant details needed to solve the problem. There is also mention of the importance of units in the answer.

ellieee
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Homework Statement
what is the numerical value of the ratio ?
Relevant Equations
Q=mcθ
Q=mc
the answer is 1/2 , but when I did the working out, I got 2/1.. so I'm quite confused
 

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The ratio has physical dimension. You therefore cannot assign a dimensionless numerical value.
 
Orodruin said:
The ratio has physical dimension. You therefore cannot assign a dimensionless numerical value.
then are you able to explain the answer key ?
 
ellieee said:
then are you able to explain the answer key ?
The question is ill posed.
 
But with regards to how the question (being ill posed) wants you to do things ...

You have taken heat capacity / specific heat capacity instead of specific heat capacity / heat capacity.
 
Orodruin said:
But with regards to how the question (being ill posed) wants you to do things ...

You have taken heat capacity / specific heat capacity instead of specific heat capacity / heat capacity.
how ..? isn't specific heat capacity = mcθ and heat capacity = cθ?
 
ellieee said:
isn't specific heat capacity = mcθ and heat capacity = cθ?
No.

Specific capacity is ‘c’ (lower case ‘c’).
Heat capacity is ‘C’ (upper case ‘C’)
C = mc
Warning: it's easy to mix up 'c' and 'C'!

That means you are simply being asked to find ##\frac c {mc}##.

Other notes...

The question contains distractors - unnecessary information to test your ability to identify the relevant information.

Q=mcΔθ gives the heat transferred when an object of mass m and specific heat capacity c changes temperature by Δθ. It is not required in this question.

Q = CΔθ gives the heat transferred when an object of heat capacity C changes temperature by Δθ. It is not required in this question.

The correct answer should have units (as already noted by @Orodruin in Post #2).

Edit - typo' corrected.
 
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