To get the truth table shown from the following logic circuit, the logic gate G should be

The Boolean expression for the given combination of logic gates is

When a small amount of impurity atoms are added to semiconductor, then generally its resistivity

The input signal given to C.E. amplifier having a voltage gain of 126 is $V_i=2 \cos \left(12 t+\frac{\pi}{3}\right)$. The corresponding output signal will be