Question

a 6 volt battery is connected to a 0.3 m wire with a diameter of 1.0mm has a current of 5. ampere flows through the wire. How much current will flow if the wire is replaced by 1.20 m wire of the same wire and diameter?

Answer 1

Gives

Battery (V)=6V

Length of wire (${l_1})=0.3m$

Daimeter (d₁)=1 mm

Diameter (d₂)=1mm

Current ($I_1$ )=5A

Length$(l_2)=1.20m$

Area both wire are same

$R=\frac{\rho l}{A}$

$V=IR$

$V=I\frac{\rho l}{A}$

Similarly we can represent

Both wire relationship

$\frac{I_1l_1}{A_1}=\frac{I_2l_2}{A_2}$

$I_2=\frac{l_1I_1}{A_1} \times\frac{A_2}{l_2}$

Put value

$$I_2=\frac{5\times0.3}{A}\times\frac{A}{1.20}=1.25A$$