Physics MCQs thread.

[cocospaniel]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s10_qp_11.pdf

Ques 28

It's D, because Electric field is uniform. so the force stays the same. Force= Q(charge) * E(electric field strength). Q doesn't change, E doesn't change, so F is the same

 

[Abdulrab]

http://www.xtremepapers.me/CIE/Internat ... _qp_12.pdf

guys do Q 21 !!! samajh nai aaraha !! please give answer wid complete explanation !! thanx

 

[DeathDealer]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s10_qp_11.pdf
Q.16 nd Q.22 plzz

Word done by car iz F*s
N
Gain in P.Energy iz mg sSin(alpha)
Efficiency = MgsSin(alpha) / Fs
Distance s in cancelled
Hence mgSin(alpha) / F

 

[RafaySid]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w09_qp_12.pdf

guys do Q 21 !!! samajh nai aaraha !! please give answer wid complete explanation !! thanx

I explained it earlier too..

Calculate stress first
=================
Stress = Force/Cross-sectional area = 20/(pi)(2.5^-4)^2 = 101.9 x 10^6 Pa

Stress/strain = Young Modulus

strain = extension/length

101.9 x 10^6/(e/l) = 2 x 10^11

Calculate the ratio (e/l)
====================
e/l = 5.1 x 10^-4

therefore for % multiply the ratio by 100, so you get (5.1 x 10^-4) x 100
= 5.1 x 10^-2 % Ans.

 

[kirashinagami]

can you help me with this?

 

[cocospaniel]

can you help me with this?

It's D, F=ke

e= (100-40)*10^-3 m
F=12 N

k= F/e = 200 Nm^-1

 

[RafaySid]

can you help me with this?

F=ke. Take force as 12N, so calculate ext i.e. 100-40 = 60mm. So k=F/e = 12/60^-3 = 200Nm^-1, D is the ans.

 

[kirashinagami]

can you help me with this?

It's D, F=ke

e= (100-40)*10^-3 m
F=12 N

k= F/e = 200 Nm^-1

thanks dude

how about this one?

 

[cocospaniel]

It's C, this website has the frequency and wavelengths that might help you http://en.wikibooks.org/wiki/A-level_Ph ... _a_wave%3F

 

[kirashinagami]

It's C, this website has the frequency and wavelengths that might help you http://en.wikibooks.org/wiki/A-level_Ph ... _a_wave%3F

thanks again..hahaha
however from the data given, it is told 'gaps of the order of 10^-5 m' what can we imply from here?

 

[cocospaniel]

It's C, this website has the frequency and wavelengths that might help you http://en.wikibooks.org/wiki/A-level_Ph ... _a_wave%3F

thanks again..hahaha
however from the data given, it is told 'gaps of the order of 10^-5 m' what can we imply from here?

When the wavelengths are about the same size of the gaps, they are significantly diffracted. The wavelength of infared rays is between 10^-4 and 10^-6. SO it's the best choice

 

[Gooners]

guyz need help in Q relating current with no of electrons.....................Q says current of 4.8 A flows thru resistor R find the direction and no of electrons flowing thru R........................ Direction is opposite to currents direction but hw do we find the no of electrons?????????
Please tell whether, change in momentum is: mv-mu or mu-mv????????????????????????????????? cuz in some Q correct frmula does matter..... thanks......

 

[cocospaniel]

guyz need help in Q relating current with no of electrons.....................Q says current of 4.8 A flows thru resistor R find the direction and no of electrons flowing thru R........................ Direction is opposite to currents direction but hw do we find the no of electrons?????????
Please tell whether, change in momentum is: mv-mu or mu-mv????????????????????????????????? cuz in some Q correct frmula does matter..... thanks......

This is not clear enough, can you tell me the question number and the year of the paper?

 

[RafaySid]

how to solve this one?

Look at the first wave. It is four squares long on X-axis, as one sq=2.5ms, 4 x 2.5 = 10ms. Thus, period is 10ms. Now horizontal line is zero level. Now count the max height above the zero level. It is a little more than 3.5 squares. As 1 sq=5mV on the Y-axis, 3.5 x 5 = 17.5 ~ 17. Thus answer is C.

 

[kirashinagami]

It's C, this website has the frequency and wavelengths that might help you http://en.wikibooks.org/wiki/A-level_Ph ... _a_wave%3F

thanks again..hahaha
however from the data given, it is told 'gaps of the order of 10^-5 m' what can we imply from here?

When the wavelengths are about the same size of the gaps, they are significantly diffracted. The wavelength of infared rays is between 10^-4 and 10^-6. SO it's the best choice

i see. ok understood.hahha

this one?

 

[Gooners]

guyz need help in Q relating current with no of electrons.....................Q says current of 4.8 A flows thru resistor R find the direction and no of electrons flowing thru R........................ Direction is opposite to currents direction but hw do we find the no of electrons?????????
Please tell whether, change in momentum is: mv-mu or mu-mv????????????????????????????????? cuz in some Q correct frmula does matter..... thanks......

This is not clear enough, can you tell me the question number and the year of the paper?

OCT/NOV 2010..............P 11 Q 31..........................................

 

[cocospaniel]

guyz need help in Q relating current with no of electrons.....................Q says current of 4.8 A flows thru resistor R find the direction and no of electrons flowing thru R........................ Direction is opposite to currents direction but hw do we find the no of electrons?????????
Please tell whether, change in momentum is: mv-mu or mu-mv????????????????????????????????? cuz in some Q correct frmula does matter..... thanks......

This is not clear enough, can you tell me the question number and the year of the paper?

OCT/NOV 2010..............P 11 Q 31..........................................

It's C. Electrons flow from negative to positive so it's Y to X. Second, the rate of flow of charge is current. So I=Q(elctron charge) / t. Elecron charge is given on the list of formulae which is 1.60 * 10^-19.
I=4.8, Q=1.60*10^-19
So rearranging the formula. you get I/Q= 1/t. Replacing I and Q you get 3 * 10^19 s^-1 hope this helps!

 

[DeathDealer]

http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf

Ques.....13 how tention iz 60 ?

 

[DeathDealer]

http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf

N also Ques 17
Y itx C ? i suggestx it wud be A !

 

[DeathDealer]

Oh dash..........tch
Same ppr. http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf
Ques 27