Question

The heat added to a thermodynamic system minus the work done is equal to which of the following?

A.the heat lost from the system
B.the internal energy
C.the total heat added to the system
D.the Carnot efficiency of the system
E.the thermodynamic increase

Answer 1

The internal energy

Step-by-step explanation:

The first law of thermodynamics states the law of conservation of energy. It gives the relationship between internal energy, work and heat added to the system. It is mathematically given as :

`\Delta U=Q-W`

Where

`\Delta U` is change in internal energy

Q is the heat added to the system

W is work done

If work is done by the system, its value is -W and if work is done on the system,its value is +W.

Hence, the correct option is (b) " the internal energy ".

Answer 2

B.the internal energy

Explanation:

To be more precise, it is equal to the variation of internal energy. In fact, this is summarized by the first law of thermodynamics, which states the following:

`\Delta U = Q-W`

where

`\Delta U` is the variation of internal energy of a system

`Q` is the heat added to the system

`W`is the work done by the system

Using this sign convention, we observe that:

- When heat is added (positive Q), the internal energy increases, while when heat is removed from the system (negative Q), the internal energy decreases

- When work is done by the system (positive W), the internal energy decreases, while when work is done by the surrounding ON the system (negative W), the internal energy increases.