The dimension of $\sqrt{\frac{\mu_0}{\epsilon_0}}$ is equal to that of (where $\mu_0 = \text{vacuum permeability}$ and $\epsilon_0 = \text{vacuum permittivity}$)

Two copper wires $A$ and $B$ have the same diameter and lengths of $3 \ cm$ and $5 \ cm$ respectively. If their resistances are $R_A$ and $R_B$ and their resistivities are $\rho_A$ and $\rho_B$,then which of the following is correct?

In the following,$I$ refers to current and other symbols have their usual meaning. Choose the option that corresponds to the dimensions of electrical conductivity.

The following figure shows cross-sections through three long conductors of the same length and material,with square cross-sections of edge lengths as shown. Conductor $B$ will fit snugly within conductor $A$,and conductor $C$ will fit snugly within conductor $B$. The relationship between their end-to-end resistance is:

$A$ wire of resistance $R$ is stretched until its radius is halved. What will be the new resistance (in $, R$)?

For a metallic wire,the ratio of voltage to corresponding current is