An object is placed \(20~\text{cm}\) in front of a concave mirror of a radius of curvature \(10~\text{cm}.\) The position of the image from the pole of the mirror is:
1. \(7.67~\text{cm}\)
2. \(6.67~\text{cm}\)
3. \(8.67~\text{cm}\)
4. \(9.67~\text{cm}\)

A \(4.5~\text{cm}\) needle is placed \(12~\text{cm}\) away from a convex mirror of focal length \(15~\text{cm}.\) What is the magnification?
1. \(0.5\)
2. \(0.56\)
3. \(0.45\)
4. \(0.15\)

A convex mirror of focal length \(f\) forms an image which is \(\frac{1}{n}\) times the length of the object. The distance of the object from the mirror is:
1. \((n-1)f\)
2. \(\left( \frac{n-1}{n} \right)f\)
3. \(\left( \frac{n+1}{n} \right)f\)
4. \((n+1)f\)

A thin rod of length \(\dfrac{f}{3}\) lies along the axis of a concave mirror of focal length \(f.\) One end of its magnified, real image touches an end of the rod. The length of the image is:

The distance between the object and its real image formed by a concave mirror is minimum when the distance of the object from the center of curvature of the mirror is: (where\(f\) is the focal length of the mirror)
1. zero
2. \(\dfrac{f}{2}\)
3. \(f\)
4. \(2f\)