State Ohm's law? How can it be verified experimentally? Does it hold good under all conditions? Comment

How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?

How will you conclude that the same potential difference exist across three resistors connected in a parallel arrangement to a battery?

Find out the following in the electric circuit given in figure
(a) Effective resistance of two 8\(\Omega\) resistors in the combination
(b) Current flowing through 4\(\Omega\) resistor. 
(c) Potential difference across 4\(\Omega\) resistance
(d) Power dissipated in 4\(\Omega\) resistor.
(e) Difference in ammeter readings, if any.

Find out the following in the electric circuit given in Figure
(a) Effective resistance of two 8 \(\Omega\) resistors in the combination
(b)Current flowing through 4 \(\Omega\) resistor
(c) Potential difference across 8 \(\Omega\) resistance
(d) Power dissipated in 4 \(\Omega\) resistor
(e) Difference in ammeter readings, if any.