Question

an object 5cm in length is held 25cm away from convex lens of focal length 10cm. what is nature, position and size of image​

Answer 1

Answer:

Given:

Height of object (h) = 5cm

distance of object (u) = -25cm [-ve by convention]

focal length (f) = 10cm

image distance (V) =?

magnification =?

lens formula,

1/f = 1/u + 1/v

or, 1/10 = 1/(-25) + 1/v

or, 1/v = 1/10 - 1/(-25)

or, 1/v = 1/10 + 1/25

or, 1/v = (5+2)/50

or, 1/v = 7/50

or, V = 50/7 cm

magnification = -V/u

or, -(50/7)/(-25)

or, 50/(7.25)

or, 2/7

The image is real , inverted and is magnified to 2/7 times .