GCSE Circuits help!

Would someone mind explaining what would happen here? My conceptual grasp of potential difference and circuits is lacking, so don't worry about being patronising.

Also the resistance question (question number 4) is causing me a lot of difficulty. Why does a longer wire lead to a greater resistance?

http://www.ocr.org.uk/Images/144867-question-paper-unit-a182-02-modules-p4-p5-p6-higher-tier.pdf

Thanks for your help. :smile:

Reply 1

Joinedup

Original post by Hariex

the first question seems to imply you've been given a before circuit and an after circuit and been asked to explain something changing - what does the full question say (including all diagrams)?

--
ρ=RA/l (usually given in formula books)

so
R=ρl/A

if ρ and A are fixed and l is variable you will see that R is proportional to l