'Optical density' of a medium is:
AThe same as mass density (ρ = m/V)
BA measure of how light slows in the medium (= refractive index); NOT the same as mass density. E.g., turpentine has lower mass density than water but higher optical density
CSimply the colour of the medium
DThe mass per unit refractive index
Answer & Solution
Correct answer: B. A measure of how light slows in the medium (= refractive index); NOT the same as mass density. E.g., turpentine has lower mass density than water but higher optical density
**Optical density ≠ mass density**. Optical density relates to the **speed of light** in the medium (effectively the refractive index). The two can be uncorrelated: turpentine (mass density ~0.85 g/mL) has *higher* optical density than water (density 1.00 g/mL).
Related questions
A reflecting telescope of the folded design is named after:A mirror used as a telescope objective is free from aberration that is:A telescope provides angular magnification of objects that are:The objective of a compound microscope forms an image that is:In a compound microscope, the lens nearest the object is the:For much larger magnification, one uses lenses numbering:The maximum magnification of a simple microscope is described as:The near point of the eye is taken as a distance of about: