Question

an object of 5.0cm in size is placed at a distance of 20.0cm from a concave mirror of focal length 15.0cm.At what distance from the mirror,should a screen be placed to get the sharp image?Also calculate the size of the image

Answer 1

Ho=5.0, u=-20,f=-15bymirror formula 1/v+1/u=1/f hence 1/v-1/20=-1/15,v=-60cmand,so m=v/u=4cm