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

[BumbleBEA]

Waves in shallow water move slower than in deep water due to greater resistance in shallow water.

Oh! My apologies, you're right. Through some stroke of luck, though, I managed to pick the right answer. Hehe...

 

[omglaigcse]

isnt it 6-7 light bulbs?
i got 7, but i think it's 6.
there's no way the answer can be 8 or more cause
for example if you say 8...so there will be 32 light bulbs
8 x 32 = 256 ohms . this is the total resistance
so the current would be:
V=IR
240 = 256I
I = 0.94A
definitely fused.

 

[Stormcry72]

isnt it 6-7 light bulbs?
i got 7, but i think it's 6.
there's no way the answer can be 8 or more cause
for example if you say 8...so there will be 32 light bulbs
8 x 32 = 256 ohms . this is the total resistance
so the current would be:
V=IR
240 = 256I
I = 0.94A
definitely fused.

but if you read the question, it says resistance increases by 5% which means resistance is now 8.4 ohms
8.4*32=268.8
V=IR
240=268.8*I
I=240/268.8
I=0.89
therefore not fused

 

[omglaigcse]

but if you read the question, it says resistance increases by 5% which means resistance is now 8.4 ohms
8.4*32=268.8
V=IR
240=268.8*I
I=240/268.8
I=0.89
therefore not fused

no. THE RESISTANCE DECREASES as the light bulb fuse
if the light bulb does not work, total resistance decreases, THAT'S WHY THE CURRENT INCREASES AND WILL FUSE.
the bulb's resistance does not increase, they are just saying that it is 0.9A, the resistance of one bulb that is left there is a 5% increase in resistance.

the type of light bulbs is the same, so there is no way suddenly a light bulb can increase by 5%, they are just assuming.

 

[Lost_Life]

they should have a range
or they will only award full marks for 8 or 9 bulbs because some people thought 31.7 should be 31 -___-

OMG I HATE THE BULBS!
btw i think that the radiation should be (half life) 2.6
since the half life of the substance ,52, is 26 then by the graph it reaches to 2.6 days

 

[Lost_Life]

for the bulbs i got 16
did anyone remember the number 144 V in that question?

 

[Lost_Life]

Yeah I knew 4 days was too long, thanks.
but I should get 3 out of 4 for understanding that we deduct and the math.

dont mind losing 1 mark, overall I guess I lost only 8-9 marks. WOW!

dont be so sure, they might correct the exam strictly

 

[kareem]

d

dont be so sure, they might correct the exam strictly

did u get 2.6 days?

 

[Rashi agarwal]

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.

dude you are so freakin' intelligent!!
even i wrote the same thing as u did!! (except some points)

 

[Jay Jun]

What's your answer for the wave? CD, CE, CF

 

[kboss]

What's your answer for the wave? CD, CE, CF

i wrote CD and something abt how waves bend away from the normal as they speed up in deeper water....

 

[Jay Jun]

i wrote CD and something abt how waves bend away from the normal as they speed up in deeper water....

if it bends away , wont it be CE ?

 

[kboss]

if it bends away , wont it be CE ?

View attachment 11226

i dunno then...it was more of a random guess....
the paper was so bloody tough anyways.....
at this point of time i am the least bothered abt it...so yeah

 

[BumbleBEA]

if it bends away , wont it be CE ?

View attachment 11226

Pretend CF is the normal

 

[B333]

Yeah i wrote CE too that was sort of the logic i went with though everyone here says its CD

 

[Chucky]

if it bends away , wont it be CE ?

View attachment 11226

draw a normal
when it moves from deep to shallow it bends towards the normal, therefore the new wavefronts will be CD
CF is out of the question (i wonder if anyone chose that)
and CE moves AWAY from normal (which is not the case here)

 

[Lost_Life]

d
did u get 2.6 days?

yup

 

[Chucky Fox]

Any idea how our total marks for the Physics paper is calculated?
I mean on what basis is it calculated?

 

[kareem]

Any idea how our total marks for the Physics paper is calculated?
I mean on what basis is it calculated?

check the w11_gt to know most likely boundaries , and they take what you got as a percentage in paper 3 for example as a percentage of the 50% and same for other papers . just add all the marks and divide by 160 and x100 is probably done

 

[Chucky]

There's a guy called chucky fox? LOL!