Answer:
Voltage across 2 cm² wire = 29.5 V
Explanation:
We equation for resistance,
[tex]R=\frac{\rho L}{A}[/tex]
Where ρ is resistivity, L is length and A is area.
Here for the four wires ρ and L is same, only area is different.
So we have
[tex]R_1:R_2:R_3:R_4=\frac{\rho L}{A_1}:\frac{\rho L}{A_2}:\frac{\rho L}{A_3}:\frac{\rho L}{A_3}\\\\R_1:R_2:R_3:R_4=\frac{1}{1}:\frac{1}{2}:\frac{1}{3}:\frac{1}{5}[/tex]
Here total voltage is given as 120 V,
In series connection voltage divides in the ratio of resistances
That is
[tex]V_1:V_2:V_3:V_4=\frac{1}{1}:\frac{1}{2}:\frac{1}{3}:\frac{1}{5}[/tex]
[tex]\frac{1}{1}\times x+\frac{1}{2}\times x+\frac{1}{3}\times x+\frac{1}{5}\times x=120Vx=59.02V[/tex]
Voltage across 2 cm² wire [tex]=\frac{59.02}{2}=29.5V[/tex]
Voltage across 2 cm² wire = 29.5 V
