Question

What is viscosity index (V.I.)?

(a) V.I.=\(\frac{L-U}{L-H}\)*100

(b) V.I.=(L-U)+(L+H)

(c) V.I.=(L-U)*(L+H)

(d) V.I.=\(\frac{L-H}{L-U}\)*100

I had been asked this question in an interview for internship.

This intriguing question comes from Lubrication System in chapter Lubrication System and Tractor’s Classification of Farm Machinery

Answer 1

Right choice is (a) V.I.=\(\frac{L-U}{L-H}\)*100

To explain: Viscosity index is an arbitrary measure for the change of viscosity with variations in temperature. The lower the VI, the greater the change of viscosity of the oil with temperature and vice versa. It is used to characterize viscosity changes with relation to temperature in lubricating oil.