Assertion: lens | /r/MadeOf | glass
Facets:
value: usually
type: TEMPORAL
value: with some other index n 2
type: OTHER
Source sentences:
text: If the lens is made of glass with some other index n 2 {\displaystyle n_{2}} , the true optical power of the surface can be obtained using
text: A lens is usually made from glass .
text: So why aren’t glasses lenses made of glass?
text: A lens is usually made from glass .