A system of natural philosophy, designed for the use of schools and academies (1845)
Moffat, J[ohn] M. [from old catalog] · Philadelphia, E. C. Biddle · leaf 375
What directions will rays generally follow after refraction by a con-cave lens ? Where is the principal focus of such a lens conceived to be situated ?- In what manner will the principal focal distance be ascertained ? How will converging rays be refracted, which, before refraction, con-verge to a… … 121. When diverging raysD A, F B, from any point Fbeyond the focus 0 fall on aconcave lens A B, they willdiverge in the directions A d,B/, as if proceeding from apoint H, between O and C;and as F advances towards C,so will H likewise: that is,the more divergent the rays arebefore refraction the…
Physics
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