Physics MCQs thread.

[Zizu1992]

http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf
Question 28 Please help

 

[arlery]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w09_qp_11.pdf
Question 28 Please help

E =F/Q

E = mg/Q

Q/m = g/E

Weight is downward so force should upward to maintain equilibrium, the direction of field is positive to negative. Negatively charged particle will experience a force acting upwards. So answer is B

 

[RafaySid]

help in nov09/11 q22 ...

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.

 

[Abdulrab]

sorry my question was from nov 06 Q 31 !!! I SENT THE WRONG LINK GUYS !! I AM REALLY SORRY

 

[Octahedral]

current=charge/time.The charge is 4Q.Frequency is 1/T.therefore I=Qxf.Charge is 4Q frequency f so 1/T =f.If u put this in the formula you'll get I=4Qf which is option A and this is the answer.

 

[RafaySid]

sorry my question was from nov 06 Q 31 !!! I SENT THE WRONG LINK GUYS !! I AM REALLY SORRY

Q=It, so I=Q/t, I=Qf
there are 4 charges and f=1, that means there is a constant flow of 4 charges in 1 second.
so I =4Qf, A is the ans.

 

[Octahedral]

Can someone please explain this?The answer to this is A

 

[arlery]

Can someone please explain this?The answer to this is A

Basically the setting is still the same. They are still in parallel, hence the voltmeter and ammeter readings will not change.

 

[RafaySid]

Can someone please explain this?The answer to this is A

The question is already asked earlier in the thread. The ans is A as the circuit is unchanged.

 

[RafaySid]

The answer is A, but can anybody explain me properly why are we subtracting the velocities? Don't we add the velocities when they are in the opp directions and subtract when they're in the same direction?? :%)

 

[unique840]

The answer is A, but can anybody explain me properly why are we subtracting the velocities? Don't we add the velocities when they are in the opp directions and subtract when they're in the same direction?? :%)

we do when we have to find the speed of approach and/or separation. in momentum, we add velocities which are in the same direction and subtract when they are in opposite directions

 

[cocospaniel]

Can someone help me in 2009 may june question 20 , i tried so many times and I keep finding A, but the mark scheme says the answer is D :fool:

 

[arlery]

e = kl/A

P : e = kl/A Q: e = k2l/0.5A
e = 4kl/A

p/q = 4kl/A divided by kl/A

answer = 4/1

 

[cocospaniel]

Thank you!!!!! I have on last question, june 2009 q 10 :unknown:

 

[arlery]

Since body was stationary before, therefore:

0 = .5mvx^2 - .5(2m)vy^2

mvy^2 = 0.5mvx^2

so m/0.5m = vx^2/vy^2

So X/Y = 2/1

 

[Octahedral]

Can someone please explain this?The ans to this is D

 

[unique840]

Can someone please explain this?The ans to this is D

s = ut + 1/2 at^2 for vertical motion
as vertical initial velocity is zero, so
s = 1/2 at^2
1.25 = 1/2*9.8*t^2
t = 0.50
s = vt for horizontal motion
10 = v*0.5
v = 20

 

[arlery]

Why is the answer C??

 

[unique840]

Why is the answer C??

grating:
m*lamda = d*sin theta
1*lamda = d*sin30
lamda = 0.5d

interference:
slit spacing = 500d
fringe spacing = (lamda*distance from screen)/slit spacing
x = (0.5d*1)/500d
x = 1*10^-3 m

 

[yubakkk]

http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w09_qp_11.pdf
Please explain Question 26.

Total maxima = 2 x highest maxima + 1

highest maxima = line spacing/wavelength

line spacing = 1/(300 x 10^-3)

highest maxima = (1/300x10^-3) /( 450 x 10^-9)

= 7.4 x 10^6

2(7.4 x 10^6) + 1 = 14.8 x 10^7

= 15 when you round it off

So answer is D

but mark sheme says D IE 14