Energy Change in Processes: Explanations Included

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SUMMARY

The discussion centers on the internal energy changes during specific physical processes: water freezing, a stone falling, water evaporating, and stretching a wire. It is established that during phase changes, such as melting and boiling, internal energy increases due to the input of heat energy, even when temperature remains constant. The participants clarify that while temperature does not change during these processes, the energy required for phase transitions results in an increase in internal energy.

PREREQUISITES
  • Understanding of thermodynamics principles
  • Knowledge of phase changes in matter
  • Familiarity with concepts of internal energy and heat transfer
  • Basic grasp of gravitational effects on objects
NEXT STEPS
  • Study the laws of thermodynamics, particularly the first law
  • Explore the concept of latent heat in phase transitions
  • Learn about the specific heat capacities of different materials
  • Investigate the relationship between temperature, pressure, and phase changes in substances
USEFUL FOR

Students of physics, educators teaching thermodynamics, and professionals in engineering or environmental science who require a deeper understanding of energy changes in physical processes.

chocofingers
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Could anybody tell whether the internal energy in the below mentioned processes is increasing , decreasing or remains the same!
And please provide explanation as well!

a) water freezing at constant temperature
b) stone falling under gravity in a vacuum
c) water evaporating at constant temperature
d) stretching a wire at constant temperature

What I believe is that it would increase in processes c & d. ?
 
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i might be wrong, but internal energy is dependent on temperature change. If temperature is constant, there should not be any change in internal energy. no?
 
yeah I too thought the same... but during melting internal energy increases ... why?? although the temperature is constant ///
 
chocofingers said:
yeah I too thought the same... but during melting internal energy increases ... why?? although the temperature is constant ///

To change the phase from solid to liquid, it takes an input of energy. This energy only causes the materiel to melt, not to increase in temperature. Once the materiel has liquified, any further energy will cause the temperature to rise again. Same thing happens when it transitions to a gas from a liquid.
 
Drakkith said:
To change the phase from solid to liquid, it takes an input of energy. This energy only causes the materiel to melt, not to increase in temperature. Once the materiel has liquified, any further energy will cause the temperature to rise again. Same thing happens when it transitions to a gas from a liquid.

So it means that during melting,boiling or any such process, internal energy remains constant ?
 
I think what drakkith is saying is, internal energy does increase in melting process as there is an input of heat energy to the substance, however temperature remains constant while melting.
 
okey thanyou, yinx & drakkith... I got it :)
 
thnxz dorebase...
 

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