Question

plz answer fast its urgent​

Answer 1

Hope the pic helps u

Answer 2

In Lens I1 ,

P=+10D

So P=1/f (in metre )

f =0.1 metre and its convex lens since focal length is positive

In Lens I2,

P=+5D

f=1/P

f=1/5 =0.2 metre and its again convex lens .

In Len I3,

P=-10D

f=1/D

f=1/-10

f=-0.1 metre and its concave lens since focal length is negative .

(Sign Convetion is important in these questions and it's very easy :) )