Heat can be converted completely into equivalent amount of work without producing changes elsewhere.

Explanation

To solve the question, we need to analyze the statement: "Heat can be converted completely into equivalent amount of work without producing changes elsewhere." We will use the principles of thermodynamics, particularly the second law, to evaluate this statement.

### Step-by-Step Solution:

1. **Understanding the Statement**: The statement suggests that heat can be entirely transformed into work without any other changes occurring in the system or surroundings.

2. **Referencing the Second Law of Thermodynamics**: According to the second law of thermodynamics, energy transformations are not 100% efficient. This law implies that while energy can be converted from one form to another, some energy is always lost as waste heat, and not all heat can be converted into work.

...