Q.Draw the circuit diagram and explain the working of CC amplifier. Also mention any two applications

A common-collector amplifier has the collector common to input and output; the signal is applied to the base and the output is taken across the emitter resistor, so the output follows the input (emitter follower). …

[!TLDR]

A CC (emitter-follower) amplifier takes its output from the emitter, which follows the base input in phase with a gain near unity; its high input and low output impedance make it an impedance-matching buffer.

Circuit: an npn transistor with the collector as the common terminal, connected to $+V_{CC}$ (AC ground). The base is biased by a voltage divider and the input signal is coupled to the base; the output is taken across the emitter resistor $R_E$, with no collector load resistor. The base-emitter junction is forward biased and the collector-base junction reverse biased.

Working: during the positive half-cycle the input raises the base voltage, increasing the base current and hence the emitter current $i_e=(1+\beta)i_b$. The larger emitter current raises the voltage across $R_E$, so the emitter (output) voltage rises in step with the base (input) — the output is in phase with the input (0°). Since almost the entire input voltage appears across $R_E$, the output voltage nearly equals the input, so the voltage gain is slightly less than unity. The emitter voltage "follows" the base, hence the name emitter follower. The current gain is high ($1+\beta$), so the stage delivers appreciable power despite the near-unity voltage gain. …