Consider an n-p-n transistor with its base-emitter junction forward biased and collector-base junction reverse biased. Which of the following statements are true?
 

a. Electrons crossover from emitter to collector
b. Holes move from base to collector
c. Electrons move from emitter to base
d. Electrons from the emitter move out of the base without going to the collector.

1. (a, d)

2. (a, c)

3. (b, c)

4. (c, d)

(a, c) Hint: The movement of the electrons depends on the biasing of the transistor.
Here emitter-base junction is forward biased i.e., the positive pole of the emitter-base battery is connected to the base and its negative pole to the emitter. Also, the collector-base junction is reverse biased, i.e., the positive pole of the collector-base battery is connected to the collector and the negative pole to the base.
Thus, electrons move from emitter to base and crossover from emitter to collector.