Question

The most desirable property amongst the following for a lubricating oil is:

• A. high density
• B. high dynamic viscosity
• C. low density
• D. low dynamic viscosity

Hint:

High dynamic viscosity is important in lubricating oils to maintain a stable oil film and reduce friction between moving parts.

Answer 1

The Correct Option is B

Lubricating oils are used to reduce friction between moving parts in machinery, engines, and other systems. The primary function of a lubricating oil is to reduce wear and tear by minimizing friction and providing a smooth surface for parts to move over. Step 1: Understand the key properties of lubricating oil.
Lubricating oils must have specific properties, such as appropriate viscosity, to provide a film of oil between the moving parts and reduce friction. Dynamic viscosity refers to the thickness or "stickiness" of the oil, which is important for maintaining a stable film of oil between surfaces.
Step 2: Analyze the options.
- (A) high density: Incorrect, as high density does not provide any significant benefit for lubricating oils.
- (B) high dynamic viscosity: Correct, as a higher viscosity helps maintain a strong oil film and reduce wear. It prevents oil from breaking down under high pressure and temperature.
- (C) low density: Incorrect, as low density does not provide the required lubrication properties.
- (D) low dynamic viscosity: Incorrect, as low viscosity oils may not form a sufficient oil film and can lead to increased friction and wear.
Thus, the correct answer is (B).