Optics 1 Question 6
6. In an experiment to determine the focal length $(f)$ of a concave mirror by the $u-v$ method, a student places the object pin $A$ on the principal axis at a distance $x$ from the pole $P$. The student looks at the pin and its inverted image from a distance keeping his/her eye in line with $P A$. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then
(2007, 3M)
(a) $x<f$
(b) $f<x<2 f$
(c) $x=2 f$
(d) $x>2 f$
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Answer:
Correct Answer: 6. (b)
Solution:
- Since object and image move in opposite directions, the positioning should be as shown in the figure. Object lies between focus and centre of curvature $f<x<2 f$.
