Question

At what distance and object be placed from a convex mirror of focal length 40 cm, so as to obtain an image 1 / 5th of the size of the object.

Answer 1

Answer:

magnification (m)= height of the image/height of object here height of image is 1/5 of height of object let height of object is ho then hi is ho/5 put the value in formula ,m= ho/ho×5 ,, m is 1/5 and another formula for found object distance is m= f/f-u ,for convex mirror f is positive then 1/5=40/40-u,,, 40-u=200 then u is -160 m ans