Question

draw the picture of a concave mirror forming an image at a distance 12 cm away from its pole the focal length of the mirror is 8 cm. calculate the distance of the object from the mirror?​

Answer 1

$\sf \gray{Solution }\\ \sf \blue{ u = - 8cm} \\ \sf \blue{\: \: \: \: \: \: = - 10cm }\\ \sf \blue{\frac{1}{f} = \frac{1}{v} + \frac{1}{4} }\\ \sf \blue{ \frac{1}{ - 10} = \frac{1}{v} + \frac{1}{ - 8}} \\ \sf \blue{ \frac{1}{v } = \frac{1}{ - 10} - \frac{1}{ - 8}} \\ \sf \blue{\frac{1}{v} = \frac{1}{40} }\\ \sf \blue{m = \frac{ - v}{4} = \frac{ - 40cm}{8}}\sf \pink{ = - 5cm }$