Which British law did the Salt Satyagraha aim to break?

$I-V$ characteristic of a copper wire of length $L$ and area of cross-section $A$ is shown in figure. The slope of the curve becomes

Write the relationship between electrical resistance and electrical resistivity for a metallic conductor of cylindrical shape. Hence, derive the SI unit of electrical resistivity.

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : Size of ${\mathrm{Bk}}^{3+}$ ion is less than ${\mathrm{Np}}^{3+}$ ion.

Reason R : The above is a consequence of the lanthanide contraction.

In the light of the above statements, choose the correct answer from the options given below :

Find the resistivity of the material of a metallic conductor of length $2 \mathrm{m}$ and area of cross-section $1.4\times {10}^{-6} {\mathrm{m}}^2$. The resistance of the conductor is $0.04 \mathrm{ohm}$.

Give reason for actinides show irregularities in their electronic configuration.

Give reason: Actinoid contraction is greater from element to element than lanthanoid contraction.