unit 3 phy help(6ph07)

[JustAnotherPerson22]

june 2009 q4
why is the answer D on the ms
not C ?

 

[alex]

v is not known

 

[svenas]

v is not known

didnt get u at alll .... also the diode will not conduct in D??

 

[alex]

didnt get u at alll .... also the diode will not conduct in D??

i was talking about 3b sorry

correct answer is A for 4
c isn't the answer as the resistance/current can't be changed.

 

[svenas]

i was talking about 3b sorry

correct answer is A for 4
c isn't the answer as the resistance/current can't be changed.

yes its A..but i didnt understand u in r/c cant be changed? plz explain to me that point and it need to be changed?
also gv me sme advice abt hw to find the millimeter setting for e.g 2 m or 2 A etc?
also in the experiment question.....when we say tht we hv to measure current using ammeter and voltage using voltmeter...they also require us to say something else abt the values ... i didnt undertand tht in the ms when they say division of 2 A smthng like tht...plz try to understand my questiions..if u didnt undertand plz tell me! thxxx a lot

 

[alex]

yes its A..but i didnt understand u in r/c cant be changed? plz explain to me that point and it need to be changed?
also gv me sme advice abt hw to find the millimeter setting for e.g 2 m or 2 A etc?
also in the experiment question.....when we say tht we hv to measure current using ammeter and voltage using voltmeter...they also require us to say something else abt the values ... i didnt undertand tht in the ms when they say division of 2 A smthng like tht...plz try to understand my questiions..if u didnt undertand plz tell me! thxxx a lot

if you read the question it says that we need to find the voltage at which the diode starts conducting, so one should either vary the emf of the battery in order to vary the p.d. across the diode, or either change the resistance of the circuit, and hence the current in order to vary the pd across the diode.

the setting shall be larger than the current/voltage in the circuit but as close to it as possible.

when picking your equipment always state the precision of the equipment and if it's a voltmeter or ammeter state a suitable range. ie the voltage is expected to be 5v, so i will use an analogue voltmeter which can read up to 6v with a precision of 0.1V, 0.1V seems to be appropriate as the % uncertainty won't be that large.

 

[svenas]

if you read the question it says that we need to find the voltage at which the diode starts conducting, so one should either vary the emf of the battery in order to vary the p.d. across the diode, or either change the resistance of the circuit, and hence the current in order to vary the pd across the diode.

the setting shall be larger than the current/voltage in the circuit but as close to it as possible.

when picking your equipment always state the precision of the equipment and if it's a voltmeter or ammeter state a suitable range. ie the voltage is expected to be 5v, so i will use an analogue voltmeter which can read up to 6v with a precision of 0.1V, 0.1V seems to be appropriate as the % uncertainty won't be that large.

aha thx a lot..thats so useful..i ll send u any other problem u helped a lot!...also what experiment u thnk will come or from which unit atleast?

 

[Hamzeh S]

if you read the question it says that we need to find the voltage at which the diode starts conducting, so one should either vary the emf of the battery in order to vary the p.d. across the diode, or either change the resistance of the circuit, and hence the current in order to vary the pd across the diode.

the setting shall be larger than the current/voltage in the circuit but as close to it as possible.

when picking your equipment always state the precision of the equipment and if it's a voltmeter or ammeter state a suitable range. ie the voltage is expected to be 5v, so i will use an analogue voltmeter which can read up to 6v with a precision of 0.1V, 0.1V seems to be appropriate as the % uncertainty won't be that large.

Can i ask u why 6 not 5 ? and why did u choose 0.1 v precision ? do i have to states the precision or just the range oh and can u give me any notes or tips u got about unit 3b one more question the diode question the answer is D in the mark scheme why ? :/ thx
1 more thing the question about the GPA thing my value was 14.7 GPA but in markscheme he said 10^10 can mean anything from 5.0 x 10 9 to 4.9 x1010 so my answer is within range i dont get it

 

[svenas]

yes also that question i didnt understand abt the 10^10??

 

[JustAnotherPerson22]

yo, the ms says D about question 4?
But your answer sounds a lot more logical

 

[Hamzeh S]

yes also that question i didnt understand abt the 10^10??

i think that 14.9GPA is 14.9x10^9 or 1.49x10^10 so 1.49 is close to 1x10^10

 

[Hamzeh S]

yo, the ms says D about question 4?
But your answer sounds a lot more logical

i think the markscheme meant question 3b instead of 4

 

[meisen]

Guys what does interpolation of analogue scale mean?

 

[svenas]

Guys what does interpolation of analogue scale mean?

where is this?which paper?

 

[alex]

yo, the ms says D about question 4?
But your answer sounds a lot more logical

it's probably a mistake. Circuits A and D are identical, but D won't work.

Can i ask u why 6 not 5 ? and why did u choose 0.1 v precision ? do i have to states the precision or just the range oh and can u give me any notes or tips u got about unit 3b one more question the diode question the answer is D in the mark scheme why ? :/ thx
1 more thing the question about the GPA thing my value was 14.7 GPA but in markscheme he said 10^10 can mean anything from 5.0 x 10 9 to 4.9 x1010 so my answer is within range i dont get it

a 5v meter would work as well. i chose 0.1V as it is small enough and one can read for V which is relatively precise. It could be 0.01V or something similar.

14.7 GPa= 1.47x10^10
10^10= 1x10^10, this has obviously been rounded to 2 s.f. so the true value lies somewhere between 0.5X10^10 and 4.9x10^10 (just think about it, if it were 5x10^10, then it'd be rounded up to 10^11 and not 10^10, so 4.9x10^10 rounds down to 1x10^10), so 1.47x10^10 is within that range. This is a retarded question, i didn't get it at first, all you should learn that when an answer is quoted in standard form, then it's has been rounded.

aha thx a lot..thats so useful..i ll send u any other problem u helped a lot!...also what experiment u thnk will come or from which unit atleast?

i think young modulus or viscosity probably (?) not sure, not an electricity experiment in my opinion.

 

[alex]

Guys what does interpolation of analogue scale mean?

If i'm not mistaken it is when you're trying to read a value to a higher precision than you should . ie an analogue ruler can read accurately to 1mm, but ie the thickness the object lies somewhere between two successive lines on the ruler, one could argue that the reading is 13.5mm instead of 13 or 14mm (this is just an example), this should be avoided as the answer cannot be more accurate than 1mm, so the answer should be rounded

 

[svenas]

if you read the question it says that we need to find the voltage at which the diode starts conducting, so one should either vary the emf of the battery in order to vary the p.d. across the diode, or either change the resistance of the circuit, and hence the current in order to vary the pd across the diode.

the setting shall be larger than the current/voltage in the circuit but as close to it as possible.

when picking your equipment always state the precision of the equipment and if it's a voltmeter or ammeter state a suitable range. ie the voltage is expected to be 5v, so i will use an analogue voltmeter which can read up to 6v with a precision of 0.1V, 0.1V seems to be appropriate as the % uncertainty won't be that large.

and for the current?

 

[svenas]

If i'm not mistaken it is when you're trying to read a value to a higher precision than you should . ie an analogue ruler can read accurately to 1mm, but ie the thickness the object lies somewhere between two successive lines on the ruler, one could argue that the reading is 13.5mm instead of 13 or 14mm (this is just an example), this should be avoided as the answer cannot be more accurate than 1mm, so the answer should be rounded

man do u thnk solving from 2009-2013 and revising unit 1 experiments is enough?

 

[svenas]

If i'm not mistaken it is when you're trying to read a value to a higher precision than you should . ie an analogue ruler can read accurately to 1mm, but ie the thickness the object lies somewhere between two successive lines on the ruler, one could argue that the reading is 13.5mm instead of 13 or 14mm (this is just an example), this should be avoided as the answer cannot be more accurate than 1mm, so the answer should be rounded

also when they say small range in critisizing...what it means? like is it the same as when they say only 4 sets of data taken?

 

[meisen]

If i'm not mistaken it is when you're trying to read a value to a higher precision than you should . ie an analogue ruler can read accurately to 1mm, but ie the thickness the object lies somewhere between two successive lines on the ruler, one could argue that the reading is 13.5mm instead of 13 or 14mm (this is just an example), this should be avoided as the answer cannot be more accurate than 1mm, so the answer should be rounded

ohh thanks! got it