1.

For a concave mirror of focal length f, image is 2 times larger. Then the object distance from the mirror can beA. `(f)/(2)`B. `(3f)/(2)`C. `(f)/(4)`D. `(4f)/(3)`

Answer» Correct Answer - A::B
If image is virtual.
Then, Suppose `u=-x`, then `v=+2x`
From the mirror formula
`(1)/(u)+(1)/(v)=(1)/(f)` or`(1)/(2x)-(1)/(x)=(1)/(-f)` or `x=(f)/(2)`
If image is real, then suppose` u=-y, ` then `v=-2y`
Again applying the mirror formula,
`(1)/(-2y)-(1)/(y)=-(1)/(f)` or `(3)/(2y)=(1)/(f)rArr y=(3)/(2)f`


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