
In semiconductor circuits, the potential drop across two p-n junctions is influenced by the forward and reverse biasing applied to them. To determine where the potential drop is equal, we analyze the scenarios in the given circuits.
Circuit Analysis:
Circuit (a): This involves two diodes connected in such a way that the applied voltage is equally divided across them, assuming ideal conditions including positive biasing in series. Therefore, the potential drop is effectively the same across both p-n junctions.
Circuit (b): The arrangement and biasing lead to an unequal distribution of the voltage across the junctions, primarily if one diode is reverse-biased or if different resistance levels affect the voltage drop.
Circuit (c): Similar to Circuit (a), it involves conditions where any connected diodes would likely be in identical forward biasing configurations, ensuring the potential drop is equal across each junction.
Thus, in Circuits (a) and (c), the conditions provided make it possible for the potential drops to be equal across the two p-n junctions, typically due to series arrangements with identical forward bias. Hence, the correct answer is both circuits (a) and (c).
Assertion (A): We cannot form a p-n junction diode by taking a slab of a p-type semiconductor and physically joining it to another slab of an n-type semiconductor.
Reason (R): In a p-type semiconductor, \( n_e \gg n_h \) while in an n-type semiconductor \( n_h \gg n_e \).
The graph shows the variation of current with voltage for a p-n junction diode. Estimate the dynamic resistance of the diode at \( V = -0.6 \) V.

Semiconductors are a crystalline solid materials, whose electrical conductivity lies between a conductor and an insulator. Semiconductors are mainly used in the manufacturing of electronic devices like capacitors, transistors, diodes, Integrated circuits, etc.