$A$ spherical mirror forms an erect image three times the linear size of the object. If the distance between the object and the image is $80 \, cm$,the focal length of the mirror is........ (in $, cm$)

  • A
    $15$
  • B
    $-15$
  • C
    $-30$
  • D
    $40$

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Similar Questions

$A$ short straight object of length $l$ lies along the central axis of a spherical concave mirror, at a distance $X$ from the mirror. The focal length of the mirror is $F$. If the length of the image in the mirror is $l^{\prime}$, then the ratio $\left(\frac{l^{\prime}}{l}\right)$ is (assume $l << X$ and $l << F$):

Consider the following statements regarding an object placed between the pole and the focus of a concave mirror: $I$. The image is real. $II$. The image is magnified. $III$. The image is erect. Which of the following is correct?

The focal length of a convex mirror is $20\, cm$. Its radius of curvature will be.....$cm$.

$A$ concave mirror of focal length '$f$' produces an image '$n$' times the size of the object. If the image is real, then the distance of the object from the mirror is

The image formed by a concave mirror is

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