When a $P-N$ junction is reverse biased,then ...

The length of a germanium rod is $0.925 \ cm$ and its area of cross-section is $1 \ mm^2$. If for germanium $n_i = 2.5 \times 10^{19} \ m^{-3}$,$\mu_h = 0.19 \ m^2/V\cdot s$,and $\mu_e = 0.39 \ m^2/V\cdot s$,then the resistance of the rod is:

Two ideal diodes are connected in the network as shown in the figure. The equivalent resistance between $A$ and $B$ is $.......\Omega$.

Which one of the diodes given below is reverse biased?

Find the value of $V_{AB}$ in the given circuit.

The voltage-current characteristic of a diode during forward bias is given by $I = 7.8 \times 10^{-5} e^{6.5 V_D}$, where $I$ is the current in $mA$ and $V_D$ is the diode voltage in $V$. Find the dynamic resistance of the diode in $\Omega$, when the current is $4 \ mA$.