2012 Higher Physics Discussion

Anyone else get that the pn junction was in Photovoltaic mode and the photons hitting it reduced the size of the depletion layer, and hence the current through the circuit increased? :confused:

I don't think I did too well on the op-amp part. :frown:

Apart from that think I got almost everything else.

i got photoconductive because there was a voltage source already present in the circuit.

Reply 541

CraigFrew

7

Original post by Tycho

Anyone else get that the pn junction was in Photovoltaic mode and the photons hitting it reduced the size of the depletion layer, and hence the current through the circuit increased? :confused:

I don't think I did too well on the op-amp part. :frown:

Apart from that think I got almost everything else.

It was photoconductive.

I think you got (ii) right, I just put current increased as it is directly proportionate to irradiance so I might only get1 mark :frown:

(edited 11 years ago)

Reply 542

Maryam A

Original post by bob169

25) a)i) 12/8=1.5A
ii) V=IR, V= 1.5*2= 3V
iii) P=IV, P=1.5*9=13.5W
26)a) line starting from origin and going up and leveling out at emf
b) I=2, V=12, Thus, R=V/I, so 6ohms
Did anyone else get these answers??

yeah i did!! :biggrin:

apart from its 2mA not 2A so the resistance was 6000 ohms

Reply 543

Blue7195

7

any chance we could attempt and make solutions? always makes me feel better when i know my rough mark haha

Reply 544

benten17

Original post by bob169

25) a)i) 12/8=1.5A
ii) V=IR, V= 1.5*2= 3V
iii) P=IV, P=1.5*9=13.5W
26)a) line starting from origin and going up and leveling out at emf
b) I=2, V=12, Thus, R=V/I, so 6ohms
Did anyone else get these answers??

I got that aswell but for 26b the current was in miliamps so the resistance was 6Kohms

Reply 545

TheZorse94

5

Original post by CraigFrew

It was photoconductive.

I think you got (ii) right, I just put current increased as it is directly proportionate to irradiance so I might only get1 mark :frown:

It's kill ohms and also mA

Reply 546

CraigFrew

7

Original post by bob169

25) a)i) 12/8=1.5A
ii) V=IR, V= 1.5*2= 3V
iii) P=IV, P=1.5*9=13.5W
26)a) line starting from origin and going up and leveling out at emf
b) I=2, V=12, Thus, R=V/I, so 6ohms
Did anyone else get these answers??

There all correct, except on 26 b) I think thats wrong, it's meant to be 6000 ohms i think

(edited 11 years ago)

Reply 547

tomathon1

Original post by bob169

25) a)i) 12/8=1.5A
ii) V=IR, V= 1.5*2= 3V
iii) P=IV, P=1.5*9=13.5W
26)a) line starting from origin and going up and leveling out at emf
b) I=2, V=12, Thus, R=V/I, so 6ohms
Did anyone else get these answers??

for 26.b. the current was in milliamps, so it was 6000 ohms :smile:

everything else i agree with tho

Reply 548

bob169

how many marks will i lose? :-(

Reply 549

Tycho

14

Anyone get that the last one was an alpha particle?

Reply 550

KeithyDee

1

http://pastebin.com/hBD6EuDN

For anyone wanting a "concise" MultiChoice answer/questions sheet.

(edited 11 years ago)

Reply 551

benten17

Original post by Tycho

Anyone get that the last one was an alpha particle?

Yeh

Reply 552

TheZorse94

5

Also R was 5k as there was already a 1k and the total was 6k

Reply 553

tomathon1

Original post by bob169

how many marks will i lose? :-(

1 or a half, depends on marking instructions :smile:

Reply 554

Herzschmerz

Some of the answers I scribbled down. They're not necessarily right! :tongue:

21a)i) 15.5km at 154 degrees
ii) 12.4kmh-1
b)i) 15.5km at 154 (same as before)
ii) 10.3kmh-1

22a)i) 61.2m
ii) 11.5m (could be 11.3 -can't read my writing) :colondollar:

b) More likely to hit tree b/c vertical velocity would be less so height at the top of it's path would be less.

23a) proof.
ii) 4.23x10^4
b) 5.6x10^-3
c) Krypton (but was unsure)

24a) P/T is a constant/ they are inversely proportional.
b) can't be bothered typing it. :wink: