mistakes: Ce/MnO4 titration & resistors problem (FH)

[MeowMix]

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I had two questions on FH that I thought were actually wrong. Would like to hear from others before I go ahead and write to AAMC.

1. on the electrochemical titration problem, I thought the Ce and MnO4 curves after the endpoint were reversed - the graphs showed that one ended up at higher voltage (MnO4?) when actually the other one should have been higher voltage. Does anyone remember this?

2. There was a three-resistor problem with a battery. Battery voltage was given, voltage drop across R1 was given, current through R2 and R3 were given. R2 and R3 were in parallel. You had to find R1.
I thought that then the current through R1 should be the sum of the current through R2 and R3, and worked out that R1 was 5 ohms. But none of the answer choices matched. I spend a long time trying to figure out another way to approach this problem. After the test, I asked an elec engineer friend and he agreed with my approach.
Did I misread the question or something?

 

[MacGyver]

You are right about #2.

If R1 is in series with the battery, and R2/R3 are in parallel with each other, then the current thru R1 = sum of currents thru R2 and R3.

 

[Deepak_nc]

so whats the answer to that question...is this the one where the power consumed ...or the power of the circuit has to be answered?
i put 200w
did i get that right...it was a guess

 

[PhatGtDmB]

deepak,
thats what i put i used P = iV (for i i added the currents up on the parrallel resistors)

 

[Koppertone]

About the voltage one.. yah I noticed that they were in the reverse order as well, but just picked what looked like the "best" answer in hopes that I at least knew part of the question. As for the second half I think I just guessed at the resistance as I ran out of time.

 

[Deepak_nc]

yeah thats the formula i used...but it didnt all add up to 200.,..for me i got some 180 or sumthing...

 

[NotShorty]

R=12Ohms sorry...

 

[NotShorty]

myspacebarisbrokenorelseI'dwritemore.Ihadtocutandpastethatspaceinthelastmessage!

 

[MeowMix]

well now I am dying of suspense - how did you get 12 ohms? did I misread the problem?

 

[NotShorty]

Yes.HadToFindR2,NotR1

 

[PhatGtDmB]

deepak,

i got an answer of 200 W exactly...

 

[Deepak_nc]

hey what did u put down as beats per min for the frog thing...i put the 130...as both stimuli will cause depolarization and cause the heart to beat and of the 140 10 could have coincided... 80+60=140

 

[PhatGtDmB]

deepak,
the answer is 80 beats per minute (This is how pacemakers work) my dad, a cardiologist, explained it to me and there are some other threads about this question. I, however, missed it and put 70🙁

 

[farleyisgod]

Originally posted by NotShorty
myspacebarisbrokenorelseI'dwritemore.Ihadtocutandpastethatspaceinthelastmessage!

🙁

 

[MeowMix]

Originally posted by NotShorty
Yes.HadToFindR2,NotR1

@$&%@@@*&%$!