$A$ $2.0 \,cm$ object is placed $15 \,cm$ in front of a concave mirror of focal length $10 \,cm$. What is the size and nature of the image?

For a concave mirror,the $\frac{1}{u}$ versus $\frac{1}{v}$ graph obtained by the parallax method is as shown in the figure. The graph is a straight line with a slope of $-1$. The estimated value of the focal length of the mirror is: (in $cm$)

$A$ small linear object is placed on the optical axis of a concave mirror. If the distance of the nearest end of the object from the mirror is greater than the radius of curvature,then:

In an experiment to determine the focal length $(f)$ of a concave mirror by the parallax method,a student places the object pin $\text{A}$ on the principal axis at a distance $x$ from the pole $\text{P}$. The student looks at the pin and its inverted image from a distance,keeping his/her eye in line with $\text{PA}$. When the student shifts his/her eye towards the left,the image appears to the right of the pin. Then:

$A$ linear object of height $10 \text{ cm}$ is kept in front of a concave mirror of radius of curvature $15 \text{ cm}$,at a distance of $10 \text{ cm}$. The image formed is

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