AP EAPCET 06-Jul-2022 Shift 1 Paper

Concave lens forms image at a distance v then using lens equation,‌‌

1

f1

=‌

1

v1

−‌

1

u1

‌⇒‌‌‌

1

−20

=‌

1

v1

−‌

1

−30

‌⇒‌‌‌

1

v1

=−‌

1

30

−‌

1

20

=‌

−50

600

⇒v1=−12‌cm so, 1st image is formed at 12‌cm left of concave lens.
Now, first image will serve as an object for convex lens.So, object distance will be 17‌cm to left of convex lens.
‌u2=−17‌cm
‌f2=+10‌cm
using lens equation again,
‌‌

1

f2

=‌

1

v2

−‌

1

u2

⇒‌‌v2=‌

170

7

=24.2‌cmfrom convex lens.
But distance between concave and convex lens is 5‌cm. Hence, image will be formed at a distance of 24.2+5=29.2‌cm to the right of concave lens.