Which one of the following does not have negative temperature coefficient?

Aluminium
Paper
Rubber
Mica

The correct answer is: Aluminium.

Aluminium has a positive temperature coefficient, which means that its resistance increases with increasing temperature. This is because the resistance of a conductor is inversely proportional to its resistivity, and the resistivity of aluminium increases with increasing temperature.

Paper, rubber, and mica all have negative temperature coefficients, which means that their resistance decreases with increasing temperature. This is because the resistance of an insulator is proportional to its resistivity, and the resistivity of these materials decreases with increasing temperature.

In conclusion, aluminium is the only material listed that does not have a negative temperature coefficient.