The external diameter of a $5 \, m$ long hollow tube is $0.1 \, m$ and the thickness of its wall is $0.005 \, m$. If the resistivity $\rho = 1.7 \times 10^{-8} \, \Omega \cdot m$, then its resistance will be:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ Alloys such as constantan and manganin are used in making standard resistance coils.
Reason $R:$ Constantan and manganin have a very small value of temperature coefficient of resistance.
In the light of the above statements, choose the correct answer from the options given below.

$A$ platinum resistance thermometer has a resistance of $50\,\Omega$ at $20\,^{\circ}C$. When dipped in a liquid,the resistance becomes $76.8\,\Omega$. The temperature coefficient of resistance for platinum is $\alpha = 3.92 \times 10^{-3}\,^{\circ}C^{-1}$. The temperature of the liquid is .............. $^{\circ}C$.

The resistance of a platinum wire at $0^{\circ}C$ is $2\,\Omega$ and $6.8\,\Omega$ at $80^{\circ}C$. The temperature coefficient of resistance of the wire is:

As the temperature increases,the electrical resistance:

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 ..... .