Resistor R₁ in the circuit below has been adjusted so that I₁ = 1 mA. The bipolar transistor Q1 and Q2 are perfectly matched and have very high current gain, so their base currents are negligible. The supply voltage V_cc is 6 V. The thermal voltage kT/q is 26 mV.

The value of R₂ (in $$\Omega $$ ) for which I₂ = 100 $$\mu {\rm A}$$ is ________.

Consider the circuit shown in the figure. Assuming V_BE1 = V_EB2 = 0.7 volt, value of the dc voltage V_c2 (in volt) is _______

If the emitter resistance in a common-emitter voltage amplifier is not bypassed, it will

A cascade connection of two voltage amplifiers A1 and A2 is shown in the figure. The open-loop gain A_v0, input resistance R_in, and output resistance R₀ for A1 and A2 are as follows:
A1: A_v0 = 10,R_in = 10 kΩ ,R₀ =1 kΩ
A2 : A_v0 = 5,R_in = 5 kΩ , R₀ = 200 Ω
The approximate overall voltage gain $$\frac{{\mathrm V}_\mathrm{out}}{{\mathrm V}_\mathrm{in}}$$ is ______.