Physics · 2017
JEE Main · 9 April 2017, Shift 1 · Q22
In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from…
In an experiment a convex lens of focal length $\displaystyle 15$ cm is placed coaxially on an optical bench in front of a convex mirror at a distance of $\displaystyle 5$ cm from it. It is found that an object and its image coincide, if the object is placed at a distance of $\displaystyle 20$ cm from the lens. The focal length of the convex mirror is :
Official answer
(1)
27.$\displaystyle 5$ cm
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JEE Main 2017 Physics question, with the answer from NTA’s final answer key. Where our answers come from.