Question

we are given a convex lens of focal length 20cm draw ray diagram to show the nature size and position of the image formed when the object is kept at a distance of 15 cm​

Answer 1

Step-by-step explanation:

Lens formula for convex lens,

v

1

−

u

1

=

f

1

v

1

−

−60

1

=

20

1

v=30 cm

Image (I

1

) formed by the convex lens acts as an object for the convex mirror.

Since the mirror and lens are separated by 15 cm, distance between I

1

and mirror is 15 cm.

i.e. u=15

For convex mirror,

f=

2

R

=10 cm

From mirror equation,

v

2

1

+

u

2

1

=

f

2

1

v

2

1

+

15

1

=

10

1

v

2

=30 cm

Hence, image is formed 30 cm right of the convex mirror.

From the ray diagram, it can be observed that the image is virtual.