InterviewSolution
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InterviewSolution
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A concave mirror has a radius of curvature of 24 cm. How far is an object from the mirror if an image is formed that is: (a) virtual and 3.0 times the size of the object, (b) real and 3.0 times the size of the object and (c) real and `1//3` the size of the object?. |
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Answer» Correct Answer - A::B::C::D Given ,`R=-24 cm` (concave mirror) Hence , `f=(R/2)=-12cm` (a) Image is virtual and 3 times larger, u is nagative and v is positive. Simultaneously ,`|v|=3|u}`.So, let, `u=-x` then `v=+3x` Substituting in the mirror formula, ` 1/v+1/u=1/f` We have, ` 1/(3x)-1/x=1/(-12)` `:. x=8cm.` Therefor , object distance is 8 cm. (b) Image is real and three times larger. Hence, u and v both are negative and `|v|=3|u|.` so let, ` u=-x` then `v=-3x` Substituting in mirror formula ,we have `(1/(-3x))+1/x=-(1)/(12)` or `x=16cm` `:.` Object distance should be 10cm. (c ) Image is real and (1/3)rd the size of object. Hence ,both u and v are negative and `|v|=(|u|)/(3).` So let , u=-x then `v=-(x/3)` Substituting in the formula, we have ` -(3/x)-(1/x)=-(1/12)` ` :. x=48 cm` `:.` Object distance should be `48cm`. |
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