An experiment is performed to determine the I - V characteristics of a Zener diode, which has a protective resistance of R = 100 $$\Omega $$, and a maximum power of dissipation rating of 1 W. The minimum voltage range of the DC source in the circuit is :

A series LR circuit is connected to a voltage source with
V(t) = V₀ sin$$\Omega $$t. After very large time, current I(t) behaves as
(t₀ >> $${L \over R}$$) :

A convex lens, of focal length 30 cm, a concave lens of focal length 120 cm, and aplane mirror are arranged as shown. For an object kept at a distance of 60 cm from the convex lens, the final image, formed by the combination, is a real image, at a distance of :