Which of the following figures represents the variation of particle momentum $p$ and the associated de-Broglie wavelength $\lambda$?

Assertion $(A)$ The effective resistance of the network between $P$ and $Q$ is $\frac{4}{5} r.$

Reason $(R):$ Symmetry can be applied to be network with respect to centre.

Which of the following is incorrect for physisorption?

If $(2, -1, 3)$ is the foot of the perpendicular drawn from the origin to a plane, then the equation of that plane is

$A$ long straight wire carrying a current of $30 ~A$ is placed in an external uniform magnetic field of induction $4 \times 10^{-4} ~T$. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point $2.0 ~cm$ away from the wire is
$\left(\mu_0=4 \pi \times 10^{-7} ~H/m\right)$

The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed $(hcp)$ crystal of '$X$' atoms are