JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Geometrical Optics

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 PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then,

(A) $x < f$
(B) $f < x < 2 f$ ✓ Correct
(C) $x = 2 f$
(D) $x > 2 f$

Answer: (B)

Solution

The parallax observation indicates the relative positions of the object and image. When the eye moves left and the image appears to move right relative to the object, it means the image is farther from the mirror than the object. For a concave mirror, this occurs when the object is between the focal point and the center of curvature, i.e.,

f < x < 2 f

JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Single correct option

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JEE Advanced · 2007 · 08 Apr 2007 · Paper 1 · Geometrical Optics

Solution

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