Question

what is the total resistance across a and b

Answer 1

here

R= R1+ R2

R1= 4 ohm

similarly = R2= 4ohm

now R1 and R2 are in parallel

1/R= ¼ + ¼
b) R= 2 ohm

here the resistance connected in middle not work due to no flow of current in it cause the potential diff is 0 there