Leaving answers in terms of constants? (1 Viewer)

[ND]

They're not gonna mark me down for this are they?

 

[Adam]

I dunno, this isn't like maths, in maths its just non-appliable answers, like 64pi units squared, in science there is a number answer.....

 

[ND]

But isn't the idea of the question to test whether the student knows what they're doing, and someone with the correct answer, regardless of its form clearly knows what they're doing. The bad thing is, i'll never know whether i get marked down because of it..

 

[t-i-m-m-y]

i reckon evaulating in physics is essential... not leaving in terms of constants

 

[ND]

Originally posted by t-i-m-m-y
i reckon evaulating in physics is essential... not leaving in terms of constants

What makes you say that?

 

[Takuya]

Originally posted by ND
What makes you say that?

You can't exactly give mass defect by leaving things in terms of u now can you...

 

[ND]

Originally posted by Takuya
You can't exactly give mass defect by leaving things in terms of u now can you...

You can give it in terms of the original mass, i don't see the problem with that (not that i did in that case).

 

[Takuya]

Originally posted by ND
You can give it in terms of the original mass, i don't see the problem with that (not that i did in that case).

Same goes for wavelength... you don't leave it as

lambda = 1/7890902R

Why not just use your calculator? I've never seen an acceptable answer written in terms of a constant. How are you going to give it to the correct number of significant figures then?

 

[ND]

If it asked for a certain number of sig figs or dec places, then i'd do it, but when they just ask for the answer, i don't see the problem.

 

[Takuya]

Originally posted by ND
If it asked for a certain number of sig figs or dec places, then i'd do it, but when they just ask for the answer, i don't see the problem.

You're always meant to give the final answer in terms of the number of significant figures given in the question. That's why they always give you something with a decimal place in, even if it's 1.0

 

[helper]

Answering in terms of sig figs is mentioned in the skills question, and as such is a requirement of the course.

 

[ND]

Hmmm ok, is there a standard amount of sig figs they want? (asking for chem)

 

[helper]

Same as what the question is in.

Eg. Data ph=6.0, then answer to two sig figs.

Molarity 2.10 or 11.1, then three sig figs.

Data ph 2, then one sig fig.

They don't normally mark sig figs but will take off marks sometimes and commonly if no numerical data.
Depends on what they are looking for in each question

 

[Adam]

The examiners comments clearly state that students get full marks if they take the formula > substitution > answer approach. Doesn't matter how you look at it, and answer of 162.23h (planks) is pretty much useless in the real world.

 

[Takuya]

Originally posted by helper
Same as what the question is in.

Eg. Data ph=6.0, then answer to two sig figs.

Molarity 2.10 or 11.1, then three sig figs.

Data ph 2, then one sig fig.

They don't normally mark sig figs but will take off marks sometimes and commonly if no numerical data.
Depends on what they are looking for in each question

They nominate 1-3 random questions which they give / take marks for significant figures in Physics and Chemistry papers.