An object is at a distance of 20 ~m from a convex lens of focal length 0.3 ~m . The lens forms an image of the object. If the object moves away from the lens at a speed of 5 ~m / s the speed and direction of the image will be

Step-by-step solution

Bylens formula array l 1 v - 1 u = 1 f 1 v - 1 (-20) = 10 3 1 v = 10 3 - 1 20 1 v = 197 60 ; v= 60 197 array Magnification of lens (m) is given by m = ( v u )= ( 60 197 ) 20 velocity of image wrt. to lens is given by v _ J / L = m ² v _ O / L direction of velocity of image is same as that of object array l v _ O / L =5 ~m / s v _ I / L = ( 60 1 197 20 )² array =1.16 10⁻³ ~m / s towards the lens