Q. A small candle, 2.5 cm in size is placed at 27cm in front of a concave mirror of radius of curvature 36cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Describe the nature and size of the image. If the candle is moved closer to the mirror, how would the screen have to be moved?

Answer

The Size of the candle h=2.5cm

Image size=h'

Object distance, u=-27cm

Radius of curvature of the concave mirror, R=-36cm

Focal length of the concave mirror,

Image distance=v

The image distance is able to be obtained using the mirror formula:

Thus, the screen must be placed 54 cm away from the mirror to obtain a sharp image.

The exaggeration of the image is given as:

The height of the candle 'spictureis 5cm. The negative sign signify that the image is inverted and virtual.

If the candle is moved closer to the mirror after that the screen will have to be moved away from the mirror in order to obtain the image.