Below given are some statements about electronic devices:
(A) Diodes can be used for rectifying an ac voltage.
(B) For semiconductors, band gap energy $E_g > 3 eV$.
(C) By changing the external applied voltage, junction barriers can be changed.
(D) p-n junction is the 'key' to all semiconductor devices.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (C) and (D) only
Analysis of the given statements:
(A) True — Diodes allow current in one direction and are used for rectifying AC voltage.
(B) False — For semiconductors, the band gap energy is typically less than 3 eV (about 1 eV).
(C) True — The applied external voltage (forward or reverse bias) changes the junction barrier potential.
(D) True — The p–n junction is fundamental to almost all semiconductor devices.
Correct statements: (A), (C), and (D)