$A$ wire of radius $r$ has resistance $R$. If it is stretched to a radius of $\frac{3r}{4}$,its resistance becomes

Masses of $3$ wires of same metal are in the ratio $1 : 2 : 3$ and their lengths are in the ratio $3 : 2 : 1$. The electrical resistances are in ratio

The specific resistance (resistivity) of material $B$ is twice that of material $A$. Two wires are prepared from these materials having the same resistance. If the diameter of wire $B$ is twice the diameter of wire $A$,then the ratio of the lengths of the two wires $l_B / l_A$ is equal to ......

We have two wires $A$ and $B$ of the same mass and same material. The diameter of wire $A$ is half that of wire $B$. If the resistance of wire $A$ is $24 \, \Omega$,then the resistance of wire $B$ will be ................ $\Omega$.

Resistance of a wire at $0^{\circ} C, 100^{\circ} C$ and $t^{\circ} C$ is found to be $10 \Omega, 10.2 \Omega$ and $10.95 \Omega$ respectively. The temperature $t$ in Kelvin scale is $\qquad$

Resistance of a tungsten wire at $150\,^{\circ}C$ is $133\,\Omega$. Its resistance temperature coefficient is $0.0045\,^{\circ}C^{-1}$. The resistance of this wire at $500\,^{\circ}C$ will be .............. $\Omega$.