24 hrs r up......full time analysis phyx P12

[Gooners]

Guys 24 hrs almost up so lets discuss the complete paper of phyx (P12)
Personally I thought the paper was easier than a lot of previous past papers but I do have some reservations bout it……………………………………..so let the discussion begin……………………………………These r all the Q I rembr…..please add any Q missed by me asthere wd b plenty
1. SIbase units of stress= (force/area)………………….not completely sure\
2. Direction of resultant etc…(XV/XH etc) I chose A =XV
3. frequency of visible spectrum, I choosed 10'14hz \
4.gradient of momentum time graph? I choose Resultant force
5. the spring mattress including 2 layers etc……….i chose B
6. elastic related Q in which we had to find force on the accerating direction.i chose 2.4N
7.Q30 in the ppr as to hw to decrease the electric fieldstrength . I chose (slightly increase d between plates)
8.the Q in which we had to find wave length by measuring the fringe width…(5.4x10'-7)\
9. if a wave can be polarized it must b -------------- ichose (transverse)
10.the efficency related Q in which it has 80 prcnt efficency……(input pwr=200 wastd=80) D
11.the hammering of nail n it wnt 5mm inside…..force?when 10 j energy blab la…I chose D=2000N,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
12. Change in momentum from240-160 in 2s find F = 40N………………………………
13. the displacemnttimegraph for ball…………….D in which the gradient bcumsconstant
14.total resistance of the circuit ………………..3 OHM
hmmmmmmmm…….thats pretty much wat I got if u hve any further Q that u guyz remember please post……………nd please answer the above Q's tooooooo……please evry single one..

 

[Talha]

ans to ur q 6 was 4.8N i.e. C.. rest r correct
for q 5 plz tel me vat were da options?

 

[junaidaftab]

Wasn't the answer to 13 A, The gradient increased and became constant in it. -.-

 

[libyafeb]

I got A for answer 13 as well, and i got the resultant force to be 4.8 like Talha

 

[libyafeb]

any ideas on the question on the glider and perfectly elastic collision? you had to select which graph was correct..

 

[hassam]

it was D for glider one

 

[junaidaftab]

What about the displacement graph? A or D?

 

[hassam]

OV COURSE aaaaa

 

[mrpaudel]

@ all: I dont know how to find ppl got 2.4 and 4.8...but most of my frens got 2.4N...and for the displacement one i wrote C...lol!!

and guys...i guess thats QN4...what are the things we need to get least uncertainty in momentum one...whats the answer for that one?

 

[mrpaudel]

and another question was.....moving +vely charge from X to Y....like..it will feel more repulsive force on radially outward field (B) or uniform filed(D)??/ i wrote B for this one...and 1,4 and 6..i.e Again B for above one..the momentum one..!! tell me the answer guys!!

 

[grumpy]

gnoomers i argue you on q7
i suppose we increase the resistance of the resistor.
in this way p.d across the plates decreses.
my teacher told me increasing and decreasing the distance i.e. small doesnt have much effect

 

[Rockstar3143]

The answer of the dispalcement time graph is A and that is almost 90% confirmed. I got the force 4.8N and i think its right because tension will be in both the strings.hey guyzz what about that question in which we have to estimate the frequency of visible spectrum???

 

[Rockstar3143]

Well the answer tothe dispalcement time graph was A for sure.
The answer of the question of moving +vely charge from X to Y was B and that was quite easy.
well i thinkk that the answer to question regarding min uncertainity was D i.e. 2, 4 and 5.

 

[junaidaftab]

What about Q 30? How to decrease the electric field strength?

 

[libyafeb]

decrease electric field strength by decreasing the distance between the plates

 

[libyafeb]

frequency visible spectrum i got 10^14

 

[Gooners]

The Q stated that the V applied across the resistor was was very small i think hence if u use fomula
E =V/D so increasing D slightly wd decrease the E as V provided is comparitively small as well.....do u guyz agree?

As for the force graph ya i realize it was 4.8 as i only took tension across half the string thus 2.4N

the visible spectrum was 10^14 i think

i was hving cnfusion in the d/t graph but choose D as i thought that the as the acceleration at start is max hence rate of change of v would also b max increasing then decreasing as time passed by...in D at start the ratr of change of displacemnt was max but in A i think that rate of change of displacemnt was very less....thn with scale i measured if A /D answers had straight line at end....for terminal velocity , only D Had a straight line but A was curving upwards....(only my thought) not imposing answer on any1

As fr glidr Q i chose D as as it was prfctly elastic nd floor was frictinless

another Q guyz regrding kinematics to find something via expression like V/gt etc....
I chose D that was 2V/gt
hmm keep going guyz ...........

 

[Gooners]

Well the answer tothe dispalcement time graph was A for sure.
The answer of the question of moving +vely charge from X to Y was B and that was quite easy.
well i thinkk that the answer to question regarding min uncertainity was D i.e. 2, 4 and 5.

Yup uncertainity too wrote D....
As fr the repulsive force i think B was the answer as in C n D were in uniform electic field hence force wd remain constant at evry point hence D

 

[libyafeb]

what about the question about the resistance and length? you had to work out the new resistance of the wire? i got 2R...

 

[Gooners]

what about the question about the resistance and length? you had to work out the new resistance of the wire? i got 2R...

can u please tell the full Q . Dont really remembr this one!!!