When a potential difference of 2V is applied across a resistor, you observed a current I. When the length of the resistor is doubled without changing the thickness, what is the current observed when 2V is applied across it.
I/2
We know that R α L
So when length is doubled, R is doubled.
So, for the same 2V potential difference, since V=IR,
R is doubled ⟹ I is halved
So new current = I/2