A 1.4-cm tall flower is 4.0 cm from a spherical concave mirror. If the image of the flower is 4.0 cm tall, how far is the image from the mirror?

Question

Quizplus · Accepted Answer

The magnification (m) is the ratio of the image height to the object height, which is 4.0 cm / 1.4 cm = 2.857. Since the image is upright, the magnification is positive. The magnification is also equal to the negative ratio of the image distance (v) to the object distance (u), so m = -v/u. Solving for v gives v = -m * u = -2.857 * 4.0 cm = -11.428 cm. The negative sign indicates the image is on the same side as the object, so the distance is 11 cm.

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