What happens to the viscosity of oil as pressure is applied?

Viscosity is a measure of a fluid's resistance to flow, and it is influenced by several factors, including temperature and pressure. When pressure is applied to oil, the viscosity tends to increase. This is because the increased pressure compresses the oil molecules, making them more resistant to flow.

Higher pressure can lead to a denser fluid where molecules are packed closer together. This increased density and interaction among the molecules results in an increase in the internal friction of the fluid, which is essentially what viscosity is measuring. Therefore, the correct response regarding what happens to the viscosity of oil when pressure is applied is that it goes up. Understanding the behavior of viscosity under pressure is crucial for applications in machinery lubrication, as it affects how well the lubricant can flow and provide necessary coverage and protection to moving parts.