Two thin lens made of glass μ$$=32$$ and water μ$$=43$$ kept in contact with each other. An object is placed at point O. Assume all curved surfaces have equal radius.Match the following Columns:(A) (B) (C) (D)

Question

Two thin lens made of glass μ$$=32$$ and water  μ$$=43$$ kept in contact with each other. An object is placed at point O. Assume all curved surfaces have equal radius.Match the following Columns:(A) (B) (C) (D)

Infinity Learn · Accepted Answer

(A) Lens Makers $$Formula1fg=32$$−$$1110$$−$$1$$−$$10$$​⇒$$fg=10$$ $$cm1fw=43$$−$$11-10$$−$$1$$∞​⇒$$fw=-30$$ cmUsing concept of combination of $$lenses1fnet=1fg+1fw=110$$−$$130$$​⇒$$fnet=15cmUsing$$ lens $$formula1v-1-5=115$$ ⇒$$v=-7.5$$ cmImage is Virtual.(B) Lens Makers $$Formula1fg=32$$−$$115$$−$$1$$−$$5$$​⇒$$fg=5$$ $$cm1fw=43$$−$$11-5$$−$$1+5$$​⇒$$fw=-152$$ cmUsing concept of combination of $$lenses1fnet=1fg+1fw=15$$−$$215$$​⇒$$fnet=15cmUsing$$ lens $$formula1v-1-5=115$$ ⇒$$v=-7.5$$ cmImage is Virtual.(C) Lens Makers $$Formula1fg=32$$−$$1110$$−$$1$$−$$10$$​⇒$$fg=10$$ $$cm1fw=43$$−$$11-10$$−$$1-10$$​⇒$$fw=$$∞Using concept of combination of $$lenses1fnet=1fg+1fw=110+1$$∞​⇒$$fnet=10cmUsing$$ lens $$formula1v-1-50=110$$ ⇒$$v=+12.5$$ cmImage is Real.(D) Lens Makers $$Formula1fg=32$$−$$11-10$$−$$110$$​⇒$$fg=-10$$ $$cm1fw=43$$−$$1110$$−$$1$$∞​⇒$$fw=30$$ cmUsing concept of combination of $$lenses1fnet=1fg+1fw=-110+130$$​⇒$$fnet=-15cmUsing$$ lens $$formula1v-1u=1-15$$ ⇒$$1v=1u-115Since$$ object is real, u will always be negative. Thus, v will also be negative.Image is Virtual.

Column - I	Column – II
(A)	(p) Final image of O will be real
(B)	(q) Final image of O will be Virtual
(C)	(r) Magnitude of focal length = 10 cm
(D)	(s) Magnitude of focal length = 15 cm
	(t) Magnitude of focal length = 25 cm

The lens

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