When an object is placed 8 millimeters from a concave spherical mirror, a clear image can be projected on a screen 16 millimeters in front of the mirror. If the object has a height of 4 millimeters, the height of the image is

A12 millimeters.
B4 millimeters.
C2 millimeters.
D8 millimeters.

Verified Answer :

m = i / p

m = 16 mm / 8 mm

m = 2 mm

2 x 4 mm = 8 mm

Answer D

hope this helps!

As per the question the object is placed at a distance of 8 mm from a concave spherical  mirror.

Hence the object distance [u] = 8 mm.

As object distance is measured opposite to the direction of light,the sign for u will be negative.

Hence u = -8 mm

The image is formed at a distance of 16 mm in front of  the mirror.

Hence the image distance [v ]= 16 mm.

As V is measured opposite to the direction of light,its sign convention will be negative.

Hence v = -16 mm

The height of object is given as 4 mm.Let the object height is denoted as -   \(h_{o}\)

The transverse measurement above the principal axis is positive.hence object height will be positive.

\(h_{i} = + 4 mm\)

As per the question we are asked to calculate the image height.Let the image height is denoted as -  \(h_{i}\)

The transverse  magnification m of for spherical  mirror is given as below-

                                     \(\frac{-v}{u} =\frac{h_{i} }{h_{o} }\)

Putting the values of respective quantities we will get-

                                       \(-[\frac{-16 mm}{-8 mm} ]=\frac{h_{i} }{4}\)

                                       \(-2 =\frac{h_{i} }{4}\)

                                       \(h_{i} = -8 mm\)

Here negative sign indicates that the image is below the principal axis i.e the image is inverted.

Hence option D is right.