# Thermodynamics - Online Test

Q1. The picture of heat as a fluid was discarded in favor of the modern concept of heat as a form of energy because
Explaination / Solution:

If heat were actually a substance, as many scientists of the time believed, it was difficult to see how so much of it could be produced during the boring of a metal cannon. Rumford showed that the amount of heat was not related to the quantity of filings produced

Q2. Thermodynamics is the branch of physics that deals with.
Explaination / Solution:

Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy and work. It deals with the relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and, by extension, of the relationships between all forms of energy.

Q3. Thermodynamic state of a system is an equilibrium state
Explaination / Solution:

In thermodynamic equilibrium there are no net macroscopic flows of matter or of energy, either within a system or between systems.

Explaination / Solution:

In thermodynamics, an adiabatic wall between two thermodynamic systems does not allow heat or matter to pass across it. In theoretical investigations, it is sometimes assumed that one of the two systems is the surroundings of the other.

Q5. Diathermic wall is
Explaination / Solution:

A wall which prevents thermal interaction is known as adiabatic wall and a system enclosed within an adiabatic wall is called thermally isolated. If exchange of heat takes place between the system and surroundings through the boundary wall, the boundary is called diathermic wall.

Q6. Zeroth Law of Thermodynamics
Explaination / Solution:

The zeroth law of thermodynamics states that if twothermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

More simply:

if

It is called the zeroth (0th) law of thermodynamics because it was discovered after the others, but people thought it was more important so they wanted to give it a number before the other laws.

Q7. Internal energy of a system
Explaination / Solution:

In thermodynamics, the internal energy of a system is the energy contained within the system. It is the energy in a system arising from the relative positions and interactions of its parts.

Q8. Internal energy of a system is
Explaination / Solution:

A state function describes the equilibrium state of a system. For example, internal energy, enthalpy, and entropy are state quantities because they describe quantitatively an equilibrium state of a thermodynamic system, irrespective of how the system arrived in that state.

Q9. First Law of Thermodynamics is

The first law of thermodynamics is the application of the conservation of energy principle to heat and thermodynamic processes:

Explaination / Solution:
No Explaination.

Q10.

If Q is the energy supplied to the system U the change in internal energy, and W the work done on the environment, First Law of Thermodynamics states that

Explaination / Solution:

Heat given to a system is equal to the sum of increase in its internal energy and the work done by the system against the surroundings.