Does length not affect resistance?

Sorry, but I don’t understand how to get the red colour values :”)

not to worry, this is my style of teaching.
this is the 1st time u see this shortcut,
u not used to it. no worries :)

let's take a look at option A first:

r , A and R are the originals.

if radius is 0.5r, the new area would be 0.25A.
u wrote in the qn paper:
up r, down R right?

but u shld add:

up r, up A , down R

so conversely,
down r , down A, up R

since the new area is reduced by 4 times, the new resistance due to the reduced area is increases by 4 times.
hence, u see the 4R in red.

next, length:
u wrote in the qn paper:
up L, up R right?

so
down L, down R

for option A,
the new length is 0.5L, i,e. halved,
so the resistance is also halved.
hence, u the 0.5R in red

combine the 2 effects of area and length, u get the 2R in blue.

k? :)

Oh ok! I think I got it. If I still have doubts, can I ask again?

give me some time, i do another write-up. :)

Ok! Thank u!