Imagine rolling a sheet of paper into a cylinder and placing a bar magnet near its end as shown in the figure. What can you say about the sign of $\vec B \cdot d\vec A$ for every area element $d\vec A$ on the surface of the cylinder?

Assertion $(A)$: Magnetic flux is a vector quantity.
Reason $(R)$: Value of magnetic flux can be positive, negative, or zero.

In which of the following systems of units is $Weber$ the unit of magnetic flux?

Two circular loops of diameters $0.6 \,cm$ and $40 \,cm$ are kept coaxially with a separation of $15 \,cm$ between their centres. If a current $2 \,A$ flows through the smaller loop, then the flux linked with the bigger loop is (approximately)

Find the magnetic flux density in $Wb/m^2$,if a magnetic flux of $2 \times 10^{-3} \ Wb$ passes through a slant area $A = 10 \ cm^2$ as shown in the figure.

Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ Magnetic monopoles do not exist.
Reason $(R) :$ Magnetic field lines are continuous and form closed loops.
In the light of the above statements, choose the most appropriate answer from the options given below.