Question

which vondition in which ohm law is applicable

Answer 1

The condition is that physical condition around the circuit should be constant.
Such physical conditions can be temperature etc.

Answer 2

It is applicable only in Linear Circuits. For clearity when 
Resistance used in circuit is independent of Voltage and 
Current mean resistance not changing its value with 
increase or decrease of current or voltage.

I am not sure u check it