Physics [ 2 Marks Questions ]

The principle of a potentiometer states that the emf of the cell is directly proportional to its balancing length.
ξ ∝ l
ξ = Irl.

A material with a negative temperature coefficient is called a thermistor.
Eg:

1. Insulator
2. Semiconductor.

Thermopile is a device used to detect thermal radiation. It works on the principle of seebeck effect.

Conversion of temperature differences into electrical voltage and vice versa is known as the thermoelectric effect.

When current flows through a resistor, some of the electrical energy delivered to the resistor is converted into heat energy and it is dissipated. This heating effect of current is known as Joule’s heating effect.

The resistance of certain materials become zero below certain temperature Tc. This temperature is known as critical temperature or transition temperature.