Lenz's law is representing which fundamental conservation law?

Assertion $(A):$ The bar magnet falling vertically along the axis of the horizontal coil will have an acceleration less than $g$.
Reason $(R):$ Clockwise current is induced in the coil.

Consider the experiment shown in the figure.
$(a)$ What would you do to obtain a large deflection of the galvanometer?
$(b)$ How would you demonstrate the presence of an induced current in the absence of a galvanometer?

The law of electromagnetic induction has been used in the construction of

$A$ square wire loop of $10.0 \, cm$ side lies at right angles to a uniform magnetic field of $20 \, T$. $A$ $10 \, V$ light bulb is in series with the loop as shown in the figure. The magnetic field is decreasing steadily to zero over a time interval $\Delta t$. The bulb will shine with full brightness if $\Delta t$ is equal to.......$ms$.

The negative sign in Faraday's law represents which fact?