Question

find the position nature and size of the image formed by a convex lens of focal length 18 cm of an object 3 cm high placed at a distance 27cm from it​

Answer 1

Answer:

f= -18

object size = 3cm

u = -27

by mirror formula

1/v+1/u = 1/f

1/v+1/-27= 1/-18

1/v =1/-18+1/27

1/v = -3+2/54

1/v = -1/54

v= -54cm

m= -v/u

m = 54/-27

m = -2cm

m= h(i)/h(0)

-2 = h(i)/3

h(i) = -6cm

Answer 2

Answer:

Explanation:

Here, the image position/distance,v=?, image size, h2=?, object size, h1=3cm

object distance, u=−9cm

Focal length of concave mirror, f=−18cm

As 1v+1u=1f,∴1v=1f−1u=1−18+19=−1+218=118

v=18cm

Positive sign of v shows that the image is virtual.

Again, h2h1=−vu or h23=−18−9=2 or h2=6cm

Positive sign of h2 shows that the image is erect. Obviously, it is magnified.