Which one of the following represents forward bias diode ?

A transistor is operated in common emitter configuration at constant collector voltage V_C = 1.5 V such that a change in the base current from 100 $$\mu $$A to 150 $$\mu $$A profuces a change in the collector current from 5 mA to 10 mA. The current gain $$\beta $$ is

The following figure shows a logic gate circuit with two inputs A and B and the output C.



The voltage waveforms of A, B and C are as shown below.



The logic circuit gate is

In a p-n junction photo cell, the value of the photo-electromotive force profuced by monochromatic light is proportional to