Question

What is the difference between rheostat and resistor?

Answer 1

Rheostat is a type of variable resistance, it is a potentiometer to be precise.

Other types of variable resistance include phototransistor, LDR(light dependent resistor) whose resistance varies with light intensity, semiconductor strain gauge (resistance varying with force/pressure), Thermistor(thermally sensitive resistor) RTD(resistance temperature detector) whose resistance varies with temperature, etc.

In general, All rheostats are variable resistance but all variable resistances are not rheostat