Device Z is tested at constant temperature and the following readings are recorded: →

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

Device Z is tested at constant temperature and the following readings are recorded: (V in V,  I in A)(V\,\text{in V},\; I\,\text{in A}) → (1,0.25),  (2,0.40),  (3,0.45)(1,0.25),\; (2,0.40),\; (3,0.45). Which inference about the behaviour of Z is correct? (a) Z is non-ohmic; its resistance decreases as current increases\text{Z is non-ohmic; its resistance decreases as current increases} (b) Z is non-ohmic; its resistance increases as current increases\text{Z is non-ohmic; its resistance increases as current increases} (c) Z exhibits a negative temperature coefficient of resistance because its current rises with heating\text{Z exhibits a negative temperature coefficient of resistance because its current rises with heating} (d) Z obeys Ohm’s law since the V–I points lie on a straight line through the origin\text{Z obeys Ohm’s law since the V–I points lie on a straight line through the origin}

Related theory

Browse the problem library