Question

A 2.04-cm-high pin, when placed at a certain distance in front of a concave mirror, produces an upright image 9.00 cm high, 35.1 cm from the mirror. Find the position of the pin relative to the mirror and the image. Draw a ray diagram to illustrate.

(a) Pin-mirror distance = ?cm
(b) Pin-image distance = ?cm

Answer 1

as given:

A 2.04-cm-high pin, when placed at a certain distance in front of a concave mirror, produces an upright image 9.00 cm high, 35.1 cm from the mirror

v = 35.1 cm , h1 = 2.04 cm , h2 = 9.0 cm

magnification m = h2/h1 = - v/u [ magnified image condition where image is actual virtual and behind the mirror and upright so, v is positive]

or, 9.0/2.04 = -35.1/u

or, u = -7.956 m

(a) Pin-mirror distance = 7.956 cm [left side of mirror]
(b) Pin-image distance = 7.956 + 35.1 = 43.056 cm