Calculate the distance of an object of height `h` from a concave mirror of focal length `10 cm` so as to obtain a real image of magnification `2`.

Answer

`- 15 cm`

Explanation

Here, `u = ?, f = - 10 cm, m = -2`
As `m = (f)/( f- u) :. -2 = (- 10)/(-10 - u) = (10)/(10 + u)`
`10 = -20 - 2 u`
`2 u = -30, u = -15 cm`.