Two wires are made of two different materials whose specific resistances are in the ratio $2:3$,lengths are in the ratio $3:4$,and cross-sectional areas are in the ratio $4:5$. The ratio of their resistances is:

Resistivity of which of the following substances decreases on increasing the temperature?

Masses of three wires of copper are in the ratio of $1: 3: 5$ and their lengths are in the ratio of $5: 3: 1$. The ratio of their electrical resistances is

$A$ wire of aluminium and a wire of germanium are cooled to a temperature of $77 \,K$. Then

If there is a $0.1\%$ increase in length due to stretching, the percentage increase in its resistance will be ............ $\%$

At room temperature $(27.0^{\circ} C)$,the resistance of a heating element is $100\; \Omega$. What is the temperature (in $^{\circ} C$) of the element if the resistance is found to be $117\; \Omega$,given that the temperature coefficient of the material of the resistor is $1.70 \times 10^{-4}\; ^{\circ} C^{-1}$?