physics mcq help

[Sully17]

http://www.xtremepapers.me/CIE/Internat ... 6_qp_1.pdf

Q33 please explain too

 

[mrpaudel]

i too wanna know this..!! but my logic is this..!! for upper total resistance=1500 whereas for lower total resistance=3000...resistance in 1st is half the 2nd...so in 2nd...1/3 of total voltage moves..means 1/3 of 12=4..and for other..2/3 of 12= 8...now difference between them is 4V..giving u answer B....actually..m not sure this is the way we can do..!! but i dont find any error here..so xplained this to u!!

 

[Sully17]

your idea does kinda make sense , but there shud be something behind this like a formula , cause ive seen loads of questions like this.

 

[Zenzenzen]

your idea does kinda make sense , but there shud be something behind this like a formula , cause ive seen loads of questions like this.

The formula used in this question is the voltage divider rule, which is used to find voltage of a resistor in a series of resistors.

R(1)/R(total) x Voltage(in) = Voltage(out)

So for the top: (500/1500) x 12 = 4V
For the bottom: (2000/3000) x 12 = 8V
8V - 4V = 4V

Therefore, the answer is B.

 

[Sully17]

Wow Thats what i was looking for , thanks for reminding me

 

[mrpaudel]

thats the same thing i said...!! actually..formula may not work..but these concepts work..as far as u have concept...use that..u dont need formula for solvin.!!

 

[Zenzenzen]

thats the same thing i said...!! actually..formula may not work..but these concepts work..as far as u have concept...use that..u dont need formula for solvin.!!

Well as long as you understand the concept behind the formula its okay. Plus theres only an hour for the entire P1, so we have to save as much time as possible

 

[mrpaudel]

thats the same thing i said...!! actually..formula may not work..but these concepts work..as far as u have concept...use that..u dont need formula for solvin.!!

Well as long as you understand the concept behind the formula its okay. Plus theres only an hour for the entire P1, so we have to save as much time as possible

Actually one hour is more than enough even we dont use formulas..!! anyway..no prblm man!!