Which of the following has the lowest refractive index?

The correct answer is Air.

Key Points 

• The refractive index of a medium is a measure of how much it bends light as it passes through it.
• Air has the lowest refractive index among common materials, which is approximately 1.0003.
• Fused Quartz has a refractive index of about 1.46.
• Oil generally has a refractive index ranging from 1.46 to 1.48.
• Alcohol has a refractive index of about 1.36.
• Thus, among the given options, air has the lowest refractive index.