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प्रश्न
Select the correct option:
A concave mirror is made by cutting a portion of a hollow glass sphere of radius 30 cm. The focal length of the concave mirror is:
विकल्प
24 cm
12 cm
15 cm
60 cm
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उत्तर
15 cm
Explanation:
Radius of curvature = R = 30 cm
Focal length of concave mirror f = `"R"/2`
f = `30/2 = 15` cm
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