Physics Pp:3-Variant 2- Discussing Answers!!

[Moi]

24 hours have passed so... lets start discussing!
1) Please someone tell me what did you get for the Bulb question?? I didn't have time to solve the Qs so i just wrote the first number that came to my mind..4
2) When the magnet enters the coil, the force induced is upward or downward ? I didn't know it so i guessed it and wrote downward!
3)What did you get for the radioactivity life?? I got 1.6 days
4)The question about the tidal thingy, the water goes left or right ?? (i didn't even know what the question was about)
5) When drawing the red ray (reflection and Refraction) how do you do it ? I traced the reflection part over the blue one, but didn't do the refraction part
6) The gate where NOR, & the two ones are Not and OR Right ?? The Y had 0 (Low) and Z had 1 (High)

That's all i have to ask for now.. Note that i left some questions un answered due to time limit !!

 

[Stormcry72]

1) I couldnt complete the question but the answer is 8 or 9
2) its upward coz lenz's law states that the induced current will create a field in such a way that it opposes the change that causes the current to be induced
3) yeah even i got 1.6 days because first you had to subtract the background radiation, then halve that value, and then add the background radiation again
4) it goes from right to left during low tide
5) refraction is a bit above the blue one but reflection remains the same (i got reflection wrong)
6) yeah its NOT and OR, and Y is Low and Z is High

 

[ZiadAmr]

1) It was 9 bulbs
2)I wrote upwards
3)Not sure
4)Right i think
5)left it
6)Your answer is correct

 

[Chucky]

1) Please someone tell me what did you get for the Bulb question??

the answer is 8
let the total number of bulbs be x.
5% of original resistance is 8.4 ohms
voltage is same (source same) and the max current before the fuse melts is 0.9A
therefore current= voltage/total resistance
0.9 = 240/(x * 8.4)
the answer comes in 31.77 , round that off its 32. so the total number of bulbs is 32. difference 40-32= 8 bulbs

2) When the magnet enters the coil, the force induced is upward or downward ?

It's upwards, as the current induced in the coil , produces a magnetic field that OPPOSES the motion on the bar magnet.
therefore when it is entering the solenoid, it will produce north to repel
when it is leaving the solenoid, it will produce south to attract, overall all the forces exerted being upwards.

3)What did you get for the radioactivity life?? I got 1.6 days

it's way more. you have to deduct background radiation which was around 14 counts per minute.
you find that from the graph (it is the point after which the counts do not decrease anymore)
52-14= 38
38/2= 19 counts per minute
find out how long it took to come to 19 counts per minute.
should be more than 3 days.

4)The question about the tidal thingy, the water goes left or right ?? (i didn't even know what the question was about)

when it is low tide, meaning the sea water is at a lowe level, water moves FROM RIGHT to LEFT

5) When drawing the red ray (reflection and Refraction) how do you do it ? I traced the reflection part over the blue one, but didn't do the refraction part

I'm not sure about this, but I heard the red ray is supposed to refract more, so you draw one line refracting and a faint line for a partial reflection as well.
if you have drawn the reflection, you get one mark.

6) The gate where NOR, & the two ones are Not and OR Right ?? The Y had 0 (Low) and Z had 1 (High)

OR THEN NOT, remember to get that sequence correct in your drawing.
Y was 0, Z was 1.

hope that helped.

 

[ZiadAmr]

the answer is 8
let the total number of bulbs be x.
5% of original resistance is 8.4 ohms
voltage is same (source same) and the max current before the fuse melts is 0.9A
therefore current= voltage/total resistance
0.9 = 240/(x * 8.4)
the answer comes in 31.77 , round that off its 32. so the total number of bulbs is 32. difference 40-32= 8 bulbs


It's upwards, as the current induced in the coil , produces a magnetic field that OPPOSES the motion on the bar magnet.
therefore when it is entering the solenoid, it will produce north to repel
when it is leaving the solenoid, it will produce south to attract, overall all the forces exerted being upwards.



it's way more. you have to deduct background radiation which was around 14 counts per minute.
you find that from the graph (it is the point after which the counts do not decrease anymore)
52-14= 38
38/2= 19 counts per minute
find out how long it took to come to 19 counts per minute.
should be more than 3 days.

for 1) you cant round it to 32 since its a fuse and it said the minimum nb so you should keep it 31. im sure
when it is low tide, meaning the sea water is at a lowe level, water moves FROM RIGHT to LEFT



I'm not sure about this, but I heard the red ray is supposed to refract more, so you draw one line refracting and a faint line for a partial reflection as well.
if you have drawn the reflection, you get one mark.



OR THEN NOT, remember to get that sequence correct in your drawing.
Y was 0, Z was 1.

hope that helped.

For the first one, it was 9 since you cant round it to 32 because they said minimum. and if its 32 it will blow so you should use 31. im sure

 

[Moi]

the answer is 8
let the total number of bulbs be x.
5% of original resistance is 8.4 ohms
voltage is same (source same) and the max current before the fuse melts is 0.9A
therefore current= voltage/total resistance
0.9 = 240/(x * 8.4)
the answer comes in 31.77 , round that off its 32. so the total number of bulbs is 32. difference 40-32= 8 bulbs


It's upwards, as the current induced in the coil , produces a magnetic field that OPPOSES the motion on the bar magnet.
therefore when it is entering the solenoid, it will produce north to repel
when it is leaving the solenoid, it will produce south to attract, overall all the forces exerted being upwards.



it's way more. you have to deduct background radiation which was around 14 counts per minute.
you find that from the graph (it is the point after which the counts do not decrease anymore)
52-14= 38
38/2= 19 counts per minute
find out how long it took to come to 19 counts per minute.
should be more than 3 days.


when it is low tide, meaning the sea water is at a lowe level, water moves FROM RIGHT to LEFT



I'm not sure about this, but I heard the red ray is supposed to refract more, so you draw one line refracting and a faint line for a partial reflection as well.
if you have drawn the reflection, you get one mark.



OR THEN NOT, remember to get that sequence correct in your drawing.
Y was 0, Z was 1.

hope that helped.

Thx ! I did get the tidal thingy correct (yay) and i did do the correct order for the gates!
But for the radioactivity, i did subtract the 14 from 52 and got 38, but i'm not sure whether i contunued till dividing by two, or just stopped there... Men the Paper was sooo trick and hard!

 

[Moi]

1) It was 9 bulbs
2)I wrote upwards
3)Not sure
4)Right i think
5)left it
6)Your answer is correct

you left questions too ?? Not enough time right?

 

[Chucky]

They will provide a range in the mark scheme, 8- 9 should be acceptable.
the current reading is rounded off , so the total number of bulbs also comes in decimal form, so you can round it off to 32 as well.
no point fussing over this, if you got 8 or 9 its okay.

 

[Moi]

i feel like everything i studied for hard, like CRO and the peek to peek distance (that i still don't get it) and the Specific heat capacity , pressure, density ... all didn't come, like i studied them for nothing!! they're the easy ones and didn't come..so frustrating!!

 

[Moi]

They will provide a range in the mark scheme, 8- 9 should be acceptable.
the current reading is rounded off , so the total number of bulbs also comes in decimal form, so you can round it off to 32 as well.
no point fussing over this, if you got 8 or 9 its okay.

urgh why didn't 8 come to my brain before 4 did ...

 

[ZiadAmr]

you left questions too ?? Not enough time right?

Yeah i didnt have time to even look at it honestly! but curve will be in our favor

 

[Chucky]

i feel like everything i studied for hard, like CRO and the peek to peek distance (that i still don't get it) and the Specific heat capacity , pressure, density ... all didn't come, like i studied them for nothing!! they're the easy ones and didn't come..so frustrating!!

Variant one got some of those, but they were not easy either. Fully applied knowledge like ours.

if you want me to compare, yes variant 2's are a bit harder this year, but beats me why CIE does that.
sometimes variant one is harder too.

 

[Moi]

Yeah i didnt have time to even look at it honestly! but curve will be in our favor

yeah.. last years paper was easy, and the A grade was 41 and above.. i expect 30 and above for the A grade of this year! Examiners like to put us through hell !!

 

[wooowooowoo]

For the first one, it was 9 since you cant round it to 32 because they said minimum. and if its 32 it will blow so you should use 31. im sure

No, it's actually supposed to be 8 as they asked minimum bulbs. The answer was 31 POINT something as in 31. (some number here)
You cannot round this figure as it is the amount of bulbs. 40-31. (some number here) gives the answer as 8. (some number here)
You can again NOT round this figure as it is the amount of bulbs. 8. (some number here) can NOT turn into 9 as that will exceed the amount we found out through the answer.
As bulbs cannot be in decimal, it has to be 8.



That's what I think.
Oh nice avatar


Lol nevermind the information I wrote above^ - Chucky explained it well enough.
Sorry

 

[Moi]

Variant one got some of those, but they were not easy either. Fully applied knowledge like ours.

if you want me to compare, yes variant 2's are a bit harder this year, but beats me why CIE does that.
sometimes variant one is harder too.

My year is always the unlucky ones ! Whenever we go to the next year, (class, grade)... something happens...in this case, we got variant 2 !!
I bet that the AS level paper next year, when we take it, would be haredr than this year!

 

[ZiadAmr]

No, it's actually supposed to be 8 as they asked minimum bulbs. The answer was 31 POINT something as in 31. (some number here)
You cannot round this figure as it is the amount of bulbs. 40-31. (some number here) gives the answer as 8. (some number here)
You can again NOT round this figure as it is the amount of bulbs. 8. (some number here) can NOT turn into 9 as that will exceed the amount we found out through the answer.
As bulbs cannot be in decimal, it has to be 8.



That's what I think.
Oh nice avatar


Lol nevermind the information I wrote above^ - Chucky explained it well enough.
Sorry

Thanks dude, no problem

 

[yuyu_373]

My year is always the unlucky ones ! Whenever we go to the next year, (class, grade)... something happens...in this case, we got variant 2 !!
I bet that the AS level paper next year, when we take it, would be haredr than this year!

ikr Bad luck !!!! We had the worst teachers ever nd we all had to take tution and some very bad exams what else !!

 

[hredoymohammad]

Thx ! I did get the tidal thingy correct (yay) and i did do the correct order for the gates!
But for the radioactivity, i did subtract the 14 from 52 and got 38, but i'm not sure whether i contunued till dividing by two, or just stopped there... Men the Paper was sooo trick and hard!

did not they say they say resistance INCREASE by 5 percent?? n wat was the resistance of each lamp given in 1st part.???

 

[Dandelion]

guys, do you know the answer for the stupid bird ? does it stay stationary when rotated or it rotates back anticlockwise ? explain too please

 

[ZiadAmr]

rotates back