An operational amplifier is a

In the given circuit,the current $(I)$ through the battery will be $..........\,A$.

$PN-$junction diode works as an insulator if connected:

In the given options,the diode that is forward biased is

Which of the following components cannot be easily fabricated or obtained from an $IC$ (Integrated Circuit)?

As shown in the figure,a diode is connected to an external resistor. Assume that the barrier potential developed in the diode is $0.5 \ V$. Find the value of the current in the circuit in milliamperes. (in $mA$)