Transistor Action — Prelims Questions

For an NPN transistor operating in the active region, which of the following biasing conditions is correct?

An NPN transistor has a common-base current gain ($\alpha$) of 0.98. If the emitter current ($I_E$) is $10\,\text{mA}$, what is the base current ($I_B$)?

Which region of a BJT is typically the most heavily doped and why?

If the common-emitter current gain ($\beta$) of a transistor is 199, what is its common-base current gain ($\alpha$)?

In an NPN transistor, if the base current ($I_B$) is $50,\mu\text{A}$ and the collector current ($I_C$) is $4.95\,\text{mA}$, what is the emitter current ($I_E$)?

Which of the following is NOT a characteristic of the base region in a BJT designed for efficient transistor action?