Bearing oil is described as having which viscosity?

• A. Double viscosity
• B. Variable viscosity
• C. Single viscosity
• D. High viscosity

Answer: (C)

The main idea here is how lubricants are described by viscosity. Bearing oils are typically specified with a single viscosity grade, meaning they have one fixed viscosity value used for selection, rather than a range or multiple values. This makes it easier to predict the oil film thickness and bearing clearance under operating conditions.

So, bearing oil being described as having a single viscosity fits because it indicates one standard viscosity specification used for the oil, not a blend of different viscosities for different temperatures. Other descriptors like double viscosity, variable viscosity, or even just “high viscosity” aren’t the standard way to label bearing oil in this context. They don’t convey the single, fixed viscosity grading that characterizes bearing oils.