In a transistor, if $\frac{I_C}{I_E} = \alpha$ and $\frac{I_C}{I_B} = \beta$. If $\alpha$ varies between $\frac{20}{21}$ and $\frac{100}{101}$, then the value of $\beta$ lies between:

In the transistor circuit shown,assume that the voltage drop between the base and the emitter is $0.5\ V$. What will be the ratio of the voltage across resistances $R_2$ and $R_1$ in order to make this circuit function as a source of constant current,$I = 1\ mA$?

Three circuit connections of a $PNP$ transistor are given below. Which of the following represents the Common-Emitter configuration?

The output characteristics of an $n-p-n$ transistor represent, ($I_C =$ collector current, $V_{CE} =$ potential difference between collector and emitter, $I_B =$ base current, $V_{BB} =$ voltage given to base, $V_{BE} =$ the potential difference between base and emitter)

In an experiment of $CE$ configuration of $n-p-n$ transistor,the transfer characteristics are observed as given in the figure. If the input resistance is $200 \ \Omega$ and output resistance is $60 \ \Omega$,the voltage gain in this experiment will be:

For transistor action:
$(1)$ Base,emitter and collector regions should have similar size and doping concentrations.
$(2)$ The base region must be very thin and lightly doped.
$(3)$ The emitter-base junction is forward biased and base-collector junction is reverse biased.
$(4)$ Both the emitter-base junction as well as the base-collector junction are forward biased.
Which one of the following pairs of statements is correct?