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The sun of diameter (d) subtends an angle o radian at the pole of a concave mirror of focal length f. What is the diameter of the image of the sun formed by the mirror? |
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Answer» meter of the image of the sun FORMED by the mirror 2fθGiven:Diameter of the sun = dFocal LENGTH of mirror = fThe subtend angle = θ radianExplanation:The distance between sun and mirror is basically infinity.∴ u = ∞Now, on USING mirror law, we get,-1/f = 1/v + 1/uOn substituting the given values, we get,-1/f = 1/v + 1/∞-1/f = 1/v + 0-1/f = 1/v∴ -f = vThe 'negative sign' indicates real, inverted and diminished.The sun subtends an angle θ radian at the pole, we get,θ = r/fWhere, r is RADIUS of IMAGER = θf∴ d = 2r = 2fθ |
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