Question

Ohm's law is not obeyed by:

• A. electrolytes
• B. discharge tubes
• C. vacuum tubes
• D. all of these

Answer 1

Answer: (D)

all of these

Answer 2

Ohm's law is true for metallic conductors only. According to this law, if there is no change in the physical state of a conductor (such as temperature) then the ratio of the potential difference applied at its ends and the current flowing through it is a constant. If a graph be drawn between the applied potential difference $V$ and the current $i$ flowing through the conductor then it will be a straight line. Ohm's law is true for metallic conductors only. Hence, electrolytes, discharge tubes and vacuum tubes do not obey Ohm's law.