Question

two lens of power 3D and -5 Dr placed in contact form of composite length and object is placed at the distance of 50 cm from the composite lens find the position of the image​

Answer 1

Answer: hi hope this helps you

equivalent power = 3D - 5D

                             = -2D

so, the lens nature is concave.

f= 50 cm  = 0.5  m

∵ p = 1/f(m)

⇒-2D = 1/f    ⇒ f = -0.5 m

u = 50 cm = -0.5 m

we know that by lens formula,

1/f =1/v -1/u

-1/2 = 1/v - 1/-0.5

1/v =    -1/2 - 1/2

1/v  = -2/2

v = -1 m

image position is 100 cm in front of the mirror.