The typical transfer characteristics of a transistor in CE configuration is shown in figure. A load resistor of $$2 \,k \Omega$$ is connected in the collector branch of the circuit used. The input resistance of the transistor is $$0.50 \,\mathrm{k} \Omega$$. The voltage gain of the transistor is ______________.

In the circuit shown below, maximum zener diode current will be _________ $$\mathrm{mA}$$.

Two ideal diodes are connected in the network as shown in figure. The equivalent resistance between A and B is __________ $$\Omega$$.

The energy band gap of semiconducting material to produce violet (wavelength = 4000$$\mathop A\limits^o $$ ) LED is ______________ $$\mathrm{eV}$$. (Round off to the nearest integer).