The resistance of an incandescent lamp is

The resistivity of a material is found to be $10^8 \Omega \cdot m$. Then the material would be

The variation of applied potential and current flowing through a given wire is shown in the figure. The length of the wire is $31.4 \, cm$. The diameter of the wire is measured as $2.4 \, cm$. The resistivity of the given wire is measured as $x \times 10^{-3} \, \Omega \cdot cm$. The value of $x$ is . . . . . . [Take $\pi = 3.14$]

Two wires of same length and thickness having specific resistances $6 \, \Omega \, cm$ and $3 \, \Omega \, cm$ respectively are connected in parallel. The effective resistivity is $\rho \, \Omega \, cm$. The value of $\rho$ to the nearest integer is ..... .

Two conductors are made of the same material and have the same length. Conductor $A$ is a solid wire of diameter $1 \ mm$. Conductor $B$ is a hollow tube of outer diameter $2 \ mm$ and inner diameter $1 \ mm$. Find the ratio of resistance $R_A$ to $R_B$.

Two metal wires of identical dimensions are connected in series. If $\sigma_1$ and $\sigma_2$ are the conductivities of the metal wires respectively,the effective conductivity of the combination is