A wire of resistance 4 Ω is stretched to twice its original

A wire of resistance 4 Ω is stretched to twice its original length. The resistance of stretched wire would be

Resistance R =	ρl
	A

∵ l' = 2l

∴ A' =	A
	2

∴ R'ρ	2l	= 4R = 4 × 4Ω = 16Ω
	A

Therefore the resistance of new wire becomes 16 Ω