In a p-n junction diode, the behavior between the p and n ends can be understood by analyzing its resistance characteristics. When the resistance is high, the diode is in its "off" state, functioning as an open circuit or a switch that is not conducting.
In the context of this question, the resistance measurement indicates whether or not current can flow through the diode. A high resistance implies that the diode blocks current flow, akin to an open switch, while low resistance means it allows current, acting like a closed switch.
Thus, when the resistance is high, the p-n junction diode effectively acts as a switch in its "off" position, preventing current from passing through.
Therefore, the correct answer to the question is that the diode acts as a switch when the resistance between the p and n ends is high.
Assuming in forward bias condition there is a voltage drop of \(0.7\) V across a silicon diode, the current through diode \(D_1\) in the circuit shown is ________ mA. (Assume all diodes in the given circuit are identical) 
A racing track is built around an elliptical ground whose equation is given by \[ 9x^2 + 16y^2 = 144 \] The width of the track is \(3\) m as shown. Based on the given information answer the following: 
(i) Express \(y\) as a function of \(x\) from the given equation of ellipse.
(ii) Integrate the function obtained in (i) with respect to \(x\).
(iii)(a) Find the area of the region enclosed within the elliptical ground excluding the track using integration.
OR
(iii)(b) Write the coordinates of the points \(P\) and \(Q\) where the outer edge of the track cuts \(x\)-axis and \(y\)-axis in first quadrant and find the area of triangle formed by points \(P,O,Q\).