Physics Unit 2 Doubt!!!!

[xainer]

Can someone explain the last question (b) part 1 of june 2012 unit 2 phy paper please? It would be nice if an explanation is given so that I can understand hw you worked it out! Thanks!

 

[aniekan]

V = E - Ir
E= 12 ( e.m.f)
I=4.30( current)
r=0.050( internal resistance)
V =? ( terminal p.d)

V= 12 -( 4.30 x 0.050)
V =11.785 V
aprrox. = 12 V

 

[jtbteddy]

I have a question too regarding physics
In the past paper of June 2011 of Unit 2 of Edexcel, for question 5, why is the answer A? For NTCs, when temperature decreases, resistance increases and voltage increases, so why isn't the answer D?

 

[xainer]

V = E - Ir
E= 12 ( e.m.f)
I=4.30( current)
r=0.050( internal resistance)
V =? ( terminal p.d)

V= 12 -( 4.30 x 0.050)
V =11.785 V
aprrox. = 12 V

In the marking scheme, they have used 0.65 as resistance..why is that???

 

[aniekan]

I don't know. it's supposed to be Internal resistance not resistance in the circuit. Well at-times the mark-scheme is confusing. Just use what you know.

 

[aniekan]

I have a question too regarding physics
In the past paper of June 2011 of Unit 2 of Edexcel, for question 5, why is the answer A? For NTCs, when temperature decreases, resistance increases and voltage increases, so why isn't the answer D?

NTC is based on the relationship between Current and Resistance. You decrease the temp. , the resistance increases hence the current decreases. So the ammeter reading will decrease.

 

[xainer]

I don't know. it's supposed to be Internal resistance not resistance in the circuit. Well at-times the mark-scheme is confusing. Just use what you know.

Oh..so using that resistance also gives about 12, right? That's where I got confused..okay thanks!!

 

[NaSiR HoSsAiN!!!]

Cud someone plz explain me the June-10 MCQ no.10(how to find the current from that graph??? )

 

[Bassem]

in jan2013, how to find the answer of q5? :s

 

[Bassem]

Cud someone plz explain me the June-10 MCQ no.10(how to find the current from that graph??? )

the point at which the 2 graphs have the same resistance (same slope), which is at 0.3A