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Light Reflection and Refraction
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12/08/2021 12:57 pm
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A man holds a spherical shaving mirror of radius of curvature 60 cm, and focal length 30 cm, at a distance of 15 cm, from his nose. Find the position of image, and calculate the magnification.
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12/08/2021 1:02 pm
Radius of curvature, R = -60 cm (concave mirror)
f = -30 cm, u = -15 cm
We have
\(\frac{1}{v}\) + \(\frac{1}{u}\) = \(\frac{1}{f}\)
\(\frac{1}{v}\) + \(\frac{1}{-15}\) = \(\frac{1}{-30}\)
\(\frac{1}{v}\) = \(\frac{1}{15}\) + \(\frac{1}{-30}\)
\(\frac{1}{v}\) = \(\frac{1}{30}\)
v = 30 cm
m = -\(\frac{v}{u}\)
m = -\(\frac{30}{-15}\)
m = 2
So, the image is formed 30 cm behind the mirror and the magnification is +2.