Question:
A conducting wire of length 'l', area of crosssection A and electric resistivity U is connected between the terminals of a battery. A potential difference V is developed between its ends, causing an electric current.
If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultant current would be :
Correct Option: 1,
Solution:
As per the question
Resistance $=\frac{\rho(2 l)}{(\mathrm{A} / 2)}=\frac{4 \rho l}{\mathrm{~A}}$
$\Rightarrow$ Current $=\frac{V}{R}=\frac{V A}{4 \rho l}$