question_answer 1)

A small candle 2.5 cm in size is placed 27 cmin front of a concave mirror of radius ofcurvature 36 cm. At what distance from themirror should a screen be placed in order toreceive a sharp image? Describe the natureand size of the image. If the candle is movedcloser to the mirror, how would the screen haveto be moved? 

Answer:

Using  and sign conventions, we get,                 or or image is formed at the distance of 54 cmfrom the mirror on the same side as theobject. This is the position where a screenshould be placed. Now magnification, The image is real, inverted and magnified. If the candle is brought closer to the mirror,the screen would have to be moved awayfrom the mirror. If the distance of the candlefrom mirror is less than 18 cm, the imagebecomes virtual and is not observable on thescreen.