Reverse bias applied to a junction diode

The current $I$ in the circuit shown below is: (All diodes are ideal and identical)

If each diode in the figure has a forward bias resistance of $25\,\Omega$ and infinite resistance in reverse bias,what will be the values of the currents $I_1, I_2, I_3,$ and $I_4$?

What is a diode?

In a forward biased $PN$-junction diode,the potential barrier in the depletion region is of the form...

The junction diode in the following circuit requires a minimum current of $1 \, mA$ to be above the knee point $(0.7 \, V)$ of its $I-V$ characteristic curve. The voltage across the diode is independent of current above the knee point. If $V_B = 5 \, V$,then the maximum value of $R$ so that the voltage is above the knee point will be: