Question 15 - POLL (1 Viewer)

[dolbinau]

Ok. Here is a poll as it's good at determining what post people got (obviously, lol)

Is 15 A, B, C, D?

 

[Aaron.Judd]

I said D.

 

[cookiemonsterz]

lol u stole my thread i blame my innability to create polls

 

[aussiechick007]

it is a simple thing we have learnt about the band theory..... CONDUCTION OCCURS IN THE CONDUCTION BAND! do we not know this?

therefore it is d

 

[Trebla]

Do you mind if you can post the whole question up (scan)?

 

[Aaron.Judd]

Is it alright if you can post the whole question up (scan)?

sure. Wait a minute.

 

[proringz]

Do you mind if you can post the whole question up (scan)?

http://img266.imageshack.us/my.php?image=q15xi7.jpg
There you go.

 

[Pwnage101]

B

 

[dolbinau]

I thought it was D because, in a P type semi conductor electrons from the conduction band fill holes in the valence band (I think). In N type semi conductors electrons are donated to conduction band from valence band.

 

[steve777]

boron is a group 3 element, and therefore the semi-conductor will be using the theory of "holes"... and the holes use valence electrons moving into the holes

its b
as the current is flowing to the right so the electrons are flowing to the left

 

[dolbinau]

Again, I don't know but - there is not enough valence electrons. One missing, so electrons flow from conduction band to fill hole. Is this wrong?

 

[steve777]

there are no electrons in the conduction band... the valence electrons are able to flow through the metal by moving into the hole in the next atoms valence band

the conduction band would be used in the p-type where there is one extra electron, which is in the cnduction band and shifts along

 

[timmiitippii]

I said B becoz the silicon block has holes in its valence band and the electrons flow from neg to pos terminal. And the movement of holes is basically the opposite of the movements of electrons so thats why i said electrons moves left in valence band.

 

[stompalot]

B
its a ptype semiconductor right? well, there is a "hole" and an electron from the "valence band" moves to fill that hole. therefore B. it cant be D, there arent any free electrons in the conduction band-only movement within the valence band.

also, even is i had no idea, i wouldnt have said D. D is just too simple especially for a Q15.

 

[alez]

D. can only conduct if electrons can move into the conduction band
valence band electrons dont matter.

 

[wLym]

voted C cause that what i put. Its not right tho im pretty sure. I had like half a minute to finish 3 multi choice questionsn =S

 

[Aaron.Judd]

Defiantly D.

 

[Shadose]

So definitely not A and C?

 

[Aaron.Judd]

Its not A or C. It is either B or D.

My physics teacher also thinks it is D.

 

[poisonives]

Defiantly D.

defiantly? lol

umm i said b) only because since its p-type doping, there is an 'acceptor' level just above the valence band in which the electrons jump into, leaving HOLES in the valence band. thus, the electrons do not actually conduct in the conduction band.