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).

The circuit diagram used to study the characteristic curve of a zener diode is connected to variable power supply (0 $$-$$ 15 V) as shown in figure. A zener diode with maximum potential V_z = 10 V and maximum power dissipation of 0.4 W is connected across a potential divider arrangement. The value of resistance R_P connected in series with the zener diode to protect it from the damage is ________________ $$\Omega$$.

A potential barrier of 0.4 V exists across a p-n junction. An electron enters the junction from the n-side with a speed of 6.0 $$\times$$ 10⁵ ms^$$-$$1. The speed with which electron enters the p side will be $${x \over 3} \times {10^5}$$ ms^$$-$$1 the value of x is _____________.

(Given mass of electron = 9 $$\times$$ 10^$$-$$31 kg, charge on electron = 1.6 $$\times$$ 10^$$-$$19 C.)