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.)

A transistor is used in an amplifier circuit in common emitter mode. If the base current changes by 100 $$\mu$$A, it brings a change of 10 mA in collector current. If the load resistance is 2 k$$\Omega$$ and input resistance is 1 k$$\Omega$$, the value of power gain is x $$\times$$ 10⁴. The value of x is _____________.

A zener of breakdown voltage V_z = 8 V and maximum zener current, I_ZM = 10 mA is subjectd to an input voltage V_i = 10 V with series resistance R = 100 $$\Omega$$. In the given circuit R_L represents the variable load resistance. The ratio of maximum and minimum value of R_L is _____________.

The cut-off voltage of the diodes (shown in figure) in forward bias is 0.6 V. The current through the resister of 40 $$\Omega$$ is __________ mA.