Question

What is the formula for A.P.I. degrees used in gravity tests for fuels?

(a) A.P.I. degrees = \(\frac{141.5}{specific \, gravity \, of \, oil \, at \, 60°F} \)-131.5

(b) A.P.I. degrees = \(\frac{131.5}{specific \, gravity \, of \, oil \, at \, 60°F} \)-141.5

(c) A.P.I. degrees = \(\frac{Specific \, gravity \, of \, oil \, at \, 60°F}{141.5} \)-131.5

(d) A.P.I. degrees = \(\frac{Specific \, gravity \, of \, oil \, at \, 60°F}{131.5} \)-141.5

This question was addressed to me in examination.

My question is taken from Fuel Supply System topic in portion Fuel Supply and Cooling System of Farm Machinery

Answer 1

The correct answer is (a) A.P.I. degrees = \(\frac{141.5}{specific \, gravity \, of \, oil \, at \, 60°F} \)-131.5

Explanation: The gravity of a fuel or an oil may be expressed as specific gravity or as an API gravity, a scale devised by American Petroleum Institute. The specific gravity of a liquid is the ratio of its weight to the weight of an equal volume of water at 60°F.