For transistor action:
(1) Base, emitter and collector regions should have similar size and doping concentrations.
(2) The base region must be vary thin and lightly doped.
(3) The emitter-base junction is forward biased and base-collector junction is reverse based.
(4) Both the emitter-base junction as well as the base-collector junction are forward biased.

Options

(a) (3), (4)
(b) (4), (1)
(c) (1), (2)
(d) (2), (3)

Correct Answer:

(2), (3)

Explanation:

For transistor action, the base region must be very thin and lightly doped. Also, the emitter-base junction is forwarded biased and base-collector junction is reverse biased.