A concave mirror has focal length f = 0.20 m. An object is placed at do = 0.30 m. What is di?

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Multiple Choice

A concave mirror has focal length f = 0.20 m. An object is placed at do = 0.30 m. What is di?

The key relation here is the mirror equation that links focal length, object distance, and image distance for a concave mirror. Using 1/f = 1/do + 1/di with f = 0.20 m and do = 0.30 m, you solve for di: 1/di = 1/f − 1/do = 1/0.20 − 1/0.30 = 5 − 3.333… = 1.666…, so di = 0.60 m. The positive di means the image is real and forms in front of the mirror. The magnification is m = −di/do = −0.60/0.30 = −2, indicating the image is inverted and twice as large as the object. Therefore the image distance is 0.60 m.

The key relation here is the mirror equation that links focal length, object distance, and image distance for a concave mirror. Using 1/f = 1/do + 1/di with f = 0.20 m and do = 0.30 m, you solve for di: 1/di = 1/f − 1/do = 1/0.20 − 1/0.30 = 5 − 3.333… = 1.666…, so di = 0.60 m. The positive di means the image is real and forms in front of the mirror. The magnification is m = −di/do = −0.60/0.30 = −2, indicating the image is inverted and twice as large as the object. Therefore the image distance is 0.60 m.

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