The resistance of p-n junction diode decreases when forward biased and increases when reverse biased. Why ?

The resistance of p-n junction is low when forward biased and is high when reverse biased. Explain.

The resistance of an ideal p-n junction diode in forward biased condition is

When p-n junction diode is forward biased then

p-n junction is called as forward biased when

A p-n junction diode is reverse biased. Then

A junction diode has a resistance of 25 Omega when forward biased and 2500 Omega when reverse biased. What is the current in the diode, for the arrangement shown ?