Answers

The Brainliest Answer!
2014-12-27T16:32:43+05:30

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Diminished erect image is formed in case of concave lens. So it is a concave lens.
object distance (u) = -2cm
image distance  = v cm
magnification (m) = +(1/4)

m = v/u
⇒ +1/4 = v/(-2)
⇒ v = -2/4 = -0.5 cm

 \frac{1}{u} + \frac{1}{v} = \frac{1}{f}  \\  \\  \frac{1}{-2} + \frac{1}{-0.5} = \frac{1}{f}  \\  \\ -0.5-2= \frac{1}{f}  \\  \\ \frac{1}{f} =-2.5 \\  \\ f =  \frac{1}{-2.5}=-0.4cm

Focal length is -0.4 cm. It is a concave lens as indicated by the negative sign of focal length.
2 5 2