In a given circuit diagram, a 5 V zener diode along with a series resistance is connected across a 50 V power supply. The minimum value of the resistance required, if the maximum zener current is 90 mA will be __________ $$\Omega$$.

A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance R_p is .................... $$\Omega$$.

For the forward biased diode characteristics shown in the figure, the dynamic resistance at I_D = 3 mA will be __________ $$\Omega$$.

The typical output characteristics curve for a transistor working in the common-emitter configuration is shown in the figure.


The estimated current gain from the figure is __________.