If in a $$p$$-$$n$$ junction diode, a square input signal of $$10$$ $$V$$ is applied as shown

Then the output signal across $${R_L}$$ will be

Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate ?

If the ratio of the concentration of electrons to that of holes in a semiconductor is $${7 \over 5}$$ and the ratio of currents is $${7 \over 4},$$ then what is the ratio of their drift velocities?

The circuit has two oppositively connected ideal diodes in parallel. What is the current following in the circuit?