PHYSICS HELP!! paper 32

[hasman123]

http://www.xtremepapers.me/CIE/Cambridg ... _qp_32.pdf

So i dont get Q9 part b... the answer to bi) in mark scheme is 2 ohm, but why? shouldnt it be 24? plz explain.
Also in bii) in markscheme answer is 6, i get that they took parallel circuits, but shouldnt it be between 2 and 8 ohm??
Plz explain it to me. THANKYOU IN ADVANCCE ;P

 

[respect1]

Part bi) It is 2 ohms because current takes the shortest way possible. It wont even go thru the 22 ohm resistor.
Part bii) It is 6 because you add the 22 and 2 ohm to give 24, this is because it is in series. Then you take the reciprocal of that and add to the reciprocal of the 6ohm resistor.
This gives us 4/24 which is 1/6 and finally you take the reciprocal of the final answer to give 6. the formula we use is (1/R1) + (1/R2)= 1/RT (RT is the total resistance.
Hope this helped you

 

[hasman123]

but in bii) why do we take 22 and 2? i thought we were to take the shortest possible way?