Answer to Question #66531 in Molecular Physics | Thermodynamics for raj jadhavar

Question

List the differences between first and second order phase transitions. What are the
characteristics of lambda transition?

Answer 1

List the differences between first and second order phase transitions.
The first order phase transitions:
1. Entropy, volume and energy of the thermodynamic system change abruptly.
2. The thermodynamic system or gives or absorbs the heat.
3 There is a temperature hysteresis

The second order phase transitions
1. Entropy, volume and energy of the thermodynamic system change continuously.
2. The thermodynamic system does not give or absorb the heat.
3. No a temperature hysteresis.

What are the characteristics of lambda transition?
It is a second-order or higher-order transition, in which the heat capacity shows either a discontinuity (second-order) or a vertex (higher-order) at the transition temperature. The Lambda point is the temperature at which normal fluid helium (helium I) makes the transition to superfluid helium II (approximately 2.17 K at 1 atmosphere). The point's name derives from the graph that results from plotting the specific heat capacity as a function of temperature, which resembles the Greek letter lambda.