Preliminary 2004 CSSA Physics (1 Viewer)

[Deliriously]

Could somebody please check the answer of 2 and 5?
I've been getting quite a lot wrong in this exam. Not sure if I'm the one making mistakes or the answers are wrong.

 

[nightweaver066]

iirc, total internal reflection is when light is refracted (bends due to change in velocity of light) such that the ray of light is at 90 degrees to the normal.

When light is slowed down, it bends away from the normal so the answer is A.

With 5, R1 and R2 are in series, so they have the same current flowing through both of them.

However in the other circuit, R3 and R4 are parallel so the current has to split to travel to both of them. Since they're of the same resistance, the current in the second circuit is halved between the two resistors so the answer is C.

 

[Deliriously]

Yay that's what I had too.
Thanks

 

[bleakarcher]

I actually got D for part 5. Say all the resistors have a resistance R, since they're identical. In the first circuit, R_T=R+R=2R. So the total current through the resistors is I_1=12/(2R)=6/R. So the current flowing through both resistors is 6/R. In the second circuit, 1/(R_T)=1/R + 1/R=2/R so R_T=R/2. So the total current through circuit 2 is I_2=12/(R/2)=24/R. But the current splits as it passes through the parallel section of the circuit so the current flowing through each resistor in circuit 2 is 12/R meaning that the current through the resistors in circuit 1 is half the current through the resistors in circuit 2.

 

[RealiseNothing]

iirc, total internal reflection is when light is refracted (bends due to change in velocity of light) such that the ray of light is at 90 degrees to the normal.

When light is slowed down, it bends away from the normal so the answer is A.

With 5, R1 and R2 are in series, so they have the same current flowing through both of them.

However in the other circuit, R3 and R4 are parallel so the current has to split to travel to both of them. Since they're of the same resistance, the current in the second circuit is halved between the two resistors so the answer is C.

It's the opposite.

When light slows down, it bends towards the normal. It bends away from the normal when it speeds up in the next medium.

Hence question 2 is B.

 

[RealiseNothing]

Question 5 is C though, the answers are wrong for that one.

 

[bleakarcher]

Question 5 is C though, the answers are wrong for that one.

How so?

 

[RealiseNothing]

How so?

The current in the first one is the same through both resistors since it is in series.

The current in the second one is split in half since it's in parallel.

That's how I interpreted it anyway.

 

[bleakarcher]

The current in the first one is the same through both resistors since it is in series.

The current in the second one is split in half since it's in parallel.

That's how I interpreted it anyway.

You're assuming the total current through both circuits is the same. It isn't though.

 

[hayabusaboston]

Question 5 is C though, the answers are wrong for that one.

its D man, the current is split so it will be half of the first one.

 

[hayabusaboston]

Question 5 is C though, the answers are wrong for that one.

No realise is right lol they tricked you with the order of the resistors, the first is twice the 2nd, you gotta read carefully. So yea the answer is C for 5

 

[Deliriously]

So what's the answer?
On closer inspection, I actually believe its D. Because initially, I thought the total current was the same in both circuits but then I realised that the current is not the same because the resistance is varied as archer proposed and working it out, the answer was D. (The working on the solutions was right).

 

[hayabusaboston]

So what's the answer?
On closer inspection, I actually believe its D. Because initially, I thought the total current was the same in both circuits but then I realised that the current is not the same because the resistance is varied as archer proposed and working it out, the answer was D. (The working on the solutions was right).

See my next post and barbenators

its D

 

[barbernator]

Q5 is D!

Voltage is conserved, and through the equation V=IR, as resistance goes up, I goes down, hence current will be less through the first resistors as they are in series and more in the second circuits as they are in parallel

 

[hayabusaboston]

So what's the answer?
On closer inspection, I actually believe its D. Because initially, I thought the total current was the same in both circuits but then I realised that the current is not the same because the resistance is varied as archer proposed and working it out, the answer was D. (The working on the solutions was right).

Its definitely C, saying its D is implying in a series circuit the current is less than in a parallel circuit, when thats impossible, because in a parallel circuit the current has more than one way to travel, so there's no way it would match the level of a series circuit where the only direction is ONE DIRECTION (Lol love the pun )

ACTUALLY WAIT ur right, I just realised that the resistance sum is different lol

 

[theind1996]

Its definitely C, saying its D is implying in a series circuit the current is less than in a parallel circuit, when thats impossible, because in a parallel circuit the current has more than one way to travel, so there's no way it would match the level of a series circuit where the only direction is ONE DIRECTION (Lol love the pun )

ACTUALLY WAIT ur right, I just realised that the resistance sum is different lol

Ah, I see that your IQ of 145 is treating you perfectly =)

 

[hayabusaboston]

Ah, I see that your IQ of 145 is treating you perfectly =)

exactly lol, thats what I meant when I said 145 not that high haha.

 

[jd2706]

Question 5 is d