What are the minimum number of 2-to 1 multiplexers required to generate a 2-input AND gate and a 2-input EX-OR gate?

The full forms of the abbreviations TTL and COMS in reference to logic families are

What are the counting states (Q₁, Q₂) for the counter shown in the figure below?

A transmission line terminates in two branches, each of length $$\lambda /4$$, as shown.The branches are terminated by 50 $$\Omega $$ loads. The lines are lossless and have the characteristic impedances shown. Determine the impedance $${Z_i}$$ as seen by the source.