Which of the following statements is correct for the Langmuir adsorption isotherm?

Activated charcoal is used to remove colouring matter from pure substances. It works by

The rate of physical adsorption:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: In expensive scientific instruments,silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason $(R)$: Silica gel adsorbs moisture from air via adsorption,thus protects the instrument from water corrosion (rusting) and/or prevents malfunctioning.
In the light of the above statements,choose the correct answer from the options given below:

The validity of the Freundlich isotherm can be verified by plotting:

Which of the following statements is incorrect w.r.t. $ \text{Physisorption} $?