Question

an object of 3 cm high is placed at a distance of 20 cm from a convex lens of focal length 12cm
please answer it's urgent​

Answer 1

Explanation:

u=−12cm

f=+8cm

ho=+3cm

Using mirror formula,

v

1

+

u

1

=

f

1

v

1

+

−30

1

=

8

1

v

1

−

30

1

=

8

1

v

1

=

8

1

+

30

1

v

1

=

60

3+2

v

1

=

60

5

=

12

1

v=+12cm

Therefore, the image will be formed at a distance of 12cm behind the mirror.

m=

um

−v

=

−30m

−12

=+0.4

m=

h

o

h

i

0.4=

h

o

h

i

0.4=

1

h

i

h

i

=+0.4cm

Answer 2

Explanation:

Please click on the pic to view the solution...

A real image is formed on the other side of the convex lens as the image distance v=+30cm

A magnified image is obtained as ... the value of m>1

$\frac{ 3}{2} = 1.5 > 1$

When we are concerned about the Magnification of the image so formed we use

H'/H in which no negative sign is put

Negative sign of magnification tells us that the image can be obtained on a screen