Physics MCQs thread.

[xHazeMx]

@hassam .. what is the answer for the density of rubber and wood question ? can u show how to get the answer ?

 

[Arshiful]

doubts!!

Is it B ?

 

[hassam]

YA SURE....1st chek the reasoning....u calculate ratio of weight using principle of moments....this will be equal to the ratio of their masses....
then....volume of wood will be times that of rubber cos of that 4l....now try it out ...nd tell me....i hope u cn reach the anser

 

[xHazeMx]

YA SURE....1st chek the reasoning....u calculate ratio of weight using principle of moments....this will be equal to the ratio of their masses....
then....volume of wood will be times that of rubber cos of that 4l....now try it out ...nd tell me....i hope u cn reach the anser

i m getting different answers of those in the choices, how can u find the ratio of weights?

 

[hassam]

applying principle of moments...be careful by taking moments from c.o.g of wood and rubber to pivot !!!

 

[xHazeMx]

applying principle of moments...be careful by taking moments from c.o.g of wood and rubber to pivot !!!

is it 2.25 ?

 

[meoooow]

can someone please explain how to do this?

 

[yubakkk]

frens over pratice is injirous to health so stop pratice

 

[xHazeMx]

can someone please explain how to do this?

B ?

 

[meoooow]

can someone please explain how to do this?

B ?

its C!

 

[abdullah181994]

 

[xHazeMx]

can someone please explain how to do this?

B ?

its C!

Oh! i forgot about the 2 wires. okay here are the calculations:
the current in the wire is 0.6 A
the resistance in ONE WIRE in the distance of 800 m = 0.005 x 800 = 4
so in the 2 wires R= 4 x 2 = 8 ohms
use the equation V = IR
V = 0.6 x 8 = 4.8 V
minimum voltage = 16 + 4.8 = 20.8 V

 

[xHazeMx]

B

 

[Zenzenzen]

Could someone help me?

Q36 in this http://www.xtremepapers.me/CIE/International A And AS Level/9702 - Physics/9702_w02_qp_1.pdf

I dont really understand what they're even asking.

 

[hassam]

yA 2.25

 

[xHazeMx]

Could someone help me?

Q36 in this http://www.xtremepapers.me/CIE/International A And AS Level/9702 - Physics/9702_w02_qp_1.pdf

I dont really understand what they're even asking.

the question is asking about the difference in voltages at X and Y. the cell provides 2 V, each of the two wires containing the 3 ( 5 ohms resistors ) will get 2 V as they are connected in parallel. in the first wire at X, the 2 V are divided by 3 since there are 3 similar resistors. so each resistor will take 2/3 V. now, at X 2/3 V has been used as it passed only 1 resistor, so the voltage at X is 4/3 V. the same with the wire at Y, same division of voltages, but the voltage is supplied to 2 resistors before it reaches Y which is 2/3 + 2/3 = 4/3 ( voltage used ) so the voltage present at Y is .. 2 - 4/3 = 2/3.
So at X the voltage in the wire is 4/3 and at Y the voltage present is 2/3. they need the potential difference between X and Y. so

4/3 - 2/3 = 2/3 V , answer is A

 

[xHazeMx]

yA 2.25

:Yahoo!:

 

[arlery]

how can I solve this? =$

 

[xHazeMx]

how can I solve this? =$

is it A ?

 

[arlery]

Yeah it's A.