Physics, Chemistry and Biology: Post your doubts here!

[GetSomeLife]

plllz nov. 2006 q3 ... why b not d ???

Umm... The answer for that IS d

 

[IGCSE O/L student]

Your welcome! Since someone already explained capacitor , I'll explain time-delay circuit.
If you understand what a capacitor does , time-delay circuits are easy. Basically..in this circuit there is a variable resistor. If you increase the resistance of this resistor the charge flowing through the capacitor decrease causing it to charge up more slowly. This INCREASES the time-delay. If resistance is decreased then more charge flows, the capacitor charges up more quickly and the time-delay is DECREASED. It's actually pretty simple x)

Jazakallahu khairan! dis ws vry helpful. thnk u vry mch!!!

 

[always-smile :)]

Umm... The answer for that IS d

oooh sorry my fault

 

[Someone2]

The levels of mercury are what shows the atm pressure. At X and Y, the pressure is same despite the different the thickness of the tube. Remember that in liquids the pressure only depends upon the density of the material and height! So, thickness has no effect

thnx!!

 

[Someone2]

does any1 hav marking scheme 4 physics may june 2010 paper 13??

 

[Just Smie :)]

does any1 hav marking scheme 4 physics may june 2010 paper 13??

It's Here,One This Site...

 

[IGCSE O/L student]

thank you so much dear! jazak ALLAH khair

wa iyyakum!

 

[ZainH]

oo yea thank you i understood now! thanks for the help and do u have nay idea about potential divider and potentiometer?

Yeah those are actually easy as well. A potential divider basically consists of two OR more resistors in series. Any voltage in the circuit is divived between both of them. A potentiometer is a variable potential divider. (This isn't the definition but to help you can think of it like a potential divider is a resistor and a potentiometer is a variable resistor)

 

[always-smile :)]

guuuuuuuuuuuuuuuuuuuuuuuuuys can some1 plllllz explain w06 no. 18 .... why c !!!!

 

[ZainH]

guuuuuuuuuuuuuuuuuuuuuuuuuys can some1 plllllz explain w06 no. 18 .... why c !!!!

I was solving that paper as well and had no clue why it was C.. I put D because it was in the middle and the heat would rise heating the tube above it.
Anyone know why its C?

 

[always-smile :)]

I was solving that paper as well and had no clue why it was C.. I put D because it was in the middle and the heat would rise heating the tube above it.
Anyone know why its C?

yeaah i did that 2

 

[ZainH]

Jazakallahu khairan! dis ws vry helpful. thnk u vry mch!!!

Im glad I could help! Your welcome x)

 

[IGCSE O/L student]

I was solving that paper as well and had no clue why it was C.. I put D because it was in the middle and the heat would rise heating the tube above it.
Anyone know why its C?

becaouse wen u heat da molecules b'cum less dense, n rise, displacin da more dense molecules. convection currents r den formed.

 

[ZainH]

becaouse wen u heat da molecules b'cum less dense, n rise, displacin da more dense molecules. convection currents r den formed.

Wow how did I not think of that! Thanks alot x)!

 

[always-smile :)]

becaouse wen u heat da molecules b'cum less dense, n rise, displacin da more dense molecules. convection currents r den formed.

yes that's the concept then what about the position why it is c not d ??

 

[IGCSE O/L student]

Wow how did I not think of that! Thanks alot x)!

ur welcum! nytym!

 

[ZainH]

yes that's the concept then what about the position why it is c not d ??

The molecules can't rise at D, there's no place for them to go up.
At C they go up the tube.

 

[GetSomeLife]

URGENT HELP NEEDED! PLEASE SOME ONE SOLVE THESE FOR ME
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s10_qp_33.pdf
question 2a (i) and (ii)

Q2)
a) i) Student B
ii) Notice that the spring stretches proportionally with the load till 12.6 and after that, it's streching rate increases. This implies that it's Limit of Elasticity is somewhere around 12.6 cm and the student crossed that!

question 6 (a)

A single beam of light with a constant frequency/wavelength is known as monochromatic light

and question 6 (F) how will i draw please explain!

At B, it will take no turn and will go STRAIGHT as there is no change in the speed (same material). When it reaches the other surface, refract it away from the normal (above)

question 8 whole question i dunno how to do

a) You just have to say:
Like charges repel
Opposite charges attract
b) Due to friction, the car becomes charged (as the friction/air resistance 'rubs' against it) This causes a shock to the person when he touches the door handle as electrons are transferred to the person!
c)
i) The negative charges (electrons) are attracted by the rod's charge and thus, move towards it. (Get collected on the right side of the ball)
ii) This is because opposite charges attract! The electrons are ATTRACTED by the positively charged rod!
iii) The negative charges from the earth flow up the body into the ball, replacing the +ve charges. Therefore, the ball becomes negatively charged!

question 9 b- y is it not 22 ohms? and (ii)

It will be 2 ohms only as 22 ohm resister will have no current through it as the current gets a better way

ii)
Total resistance = (R1*R2)/(R1+R2)
R1 is 22 + 2 = 24 ohms
R2 is 8 ohms

We use this formula because they are in parallel:

=(8*24)/(8+24)
= 6 ohms

question 10 a and b! please some one help!

a) Amplitude remains the same but you have to change it's wavelength by doing the calculation
b) If the PEAK TO PEAK height has to be increased... then you just have to INCREASE the volts/cm while keeping the TIME BASE same

 

[IGCSE O/L student]

yes that's the concept then what about the position why it is c not d ??

if u heat it @ d, da molecules will move frm both da sides, coz it is in da middle.

 

[GetSomeLife]

yes that's the concept then what about the position why it is c not d ??

Wow how did I not think of that! Thanks alot x)!

Umm which question guys?