A copper wire has a length L, a square cross-section of side length W and an end to end resistance R. Without loss of material the wire is sliced along its long direction to make 4 equal length wires of equal square cross-sections (see below). These are then welded together end-to-end to make one wire that is 4 times the original length.
What is the new resistance?
R/4
R/2
none of these
R/16
16R
2R
4R