In Fig. 14.2, assuming the diodes to be ideal,


In the given circuit, the voltage applied at A is -10 V and at B is 0 V. We know that current flows from higher potential to lower potential and therefore in this case current should flow from B to A. However, as can be seen the Diode D1 is in reverse bias as the p side of the diode is on the side of lower potential and hence no current will flow through the circuit, as a reverse biased diode allows no current. Similarly, diode D2 is forward bias and allows current to flow.

1