What is the value of current through the diode in the circuit given?

For the given logic circuit, the output Y for inputs (A = 0, B = 1) and (A = 0, B = 0) respectively are

A common emitter transistor amplifier is connected with a load resistance of 6 k$$\Omega $$ . When a small AC signal of 15 mV is added to the base-emitter voltage, the alternating base current is 20$$\mu $$A and the alternating collector current is 1.8 mA. What is the voltage gain of the amplifier?

In the circuit shown, the value of $$\beta $$ of the transistor is 48. If the supplied base current is 200 $$\mu $$A, what is the voltage at the terminal Y?